Comp 274XE cam
 

Who's using this cam in a 9.5 to 1 455 and what are your likes, dislikes and results? I see it used alot in a hot street 455 buildups lately. I have some JBP ported #96 heads (1971) flowing 240 CFM on a fresh 30 over 455 right now without a cam, intake or carb. Going in a '67 bird with 3.55 gears (optional changeout considered) and a 4-speed. Your thoughts? Suggestions?

My thoughts?

There are better cams out there. :2cents:

My suggestion...

I dunno,"off the shelf" choice,maybe the Crower #60243 or something of that sort.

Myself,I'd opt for a custom ground bumpstick.

JMO

BP.

XE274 is a ecselend cam for that engine. my frind hase it in his formula car thuse 12.12 sec in the 1/4 and he drives lots of street miles as wel with a tr2004r trans and 3.42 rear ratio, ................. http://www.youtube.com/watch?v=kghSCRQDSyc

I like it. A nice all round work horse cam for street performance. Has good vacuum too.
Have installed dozens and sold still more over the years.
The 041 cam of the new millenium. :D

Agreed with David and Ken. In a lower-compression engine, where you would have used the "041" (Ram Air IV) in a 10.5:1 application, the XE274H is the best choice.

Jim

Here's my 02 cents, again. Small cams on 110LSA's have proven themselves to me to NOT be the best direction to go, IF you want to make the most power from your medium compression ratio 455 engine.

The XE274 cam would be OK in a "low" compression 455 engine, but it will give up some upper mid-range and top end power compared to a longer duration cam on a wider LSA.

If you want your "low" compression 455 engine to idle well, and pull hard in the lower rpm's, it's an alternative for you, but there are a LOT better choices out there these days.

At 9.5 to 1 static compression, 455-472cid, no problem at all managing more camshaft than 274 degrees. I like to see 290 to about 310 degree camshafts in those applications, and prefer to sqeeze the engines just a bit more as well. The result(s) will be better everyplace than the XE274 grind.

Here are some numbers, very respectable sent to us by a customer we set up a carburetor for. 230cfm 6X-4 heads, ported iron intake, 463cid, 10 to 1 CR, 4 tube headers, XE274 camshaft. Peak HP 414 @ 4900rpm's, peak torque 587ft lbs at 3400rpm's. Looks pretty good at a glance....right?

Same set-up using the Crower 60919 camshaft, 455.4 hp @ 5600rpm's, 540 tq at 3800rpm's. This was my own engine dyno'd for the HPP head swap article when we went to the KRE heads. After installing the KRE heads, HP jumped to 494.

Here's the trump card folks, the XE274 cammed engine was clear down to 412ft lbs torque at 4900rpm's. My engine was still making over 500ft lbs torque at 5000rpm's! It also made more average torque, and HP across the rpm range, by a considerable amount.

The tight LSA grind, short seat timing, less overlap, etc, pulled the power down lower in the rpm range, and it made less power. This would NOT show up in a "seat of the pants" assessment, but will show up on an engine/chassis dyno, and at the track. Matter of fact, pulling all the power down to lower rpm's usually fools the driver of the car into thinking his engine is making MORE power. The small/tight LSA grinds are brutal down low, spins tires easily, very responsive off idle, etc.

IF this is what you want, and how you evaluate the performance of your street car, it makes the XE274 cam a fine choice for your medium compression ratio 455.

IF you want to make quite a bit more power, and spread the power out some, with a strong upper mid-range and top end charge, install a larger camshaft on a wider LSA.

There are also other benefits from going to a larger cam on a wider LSA. If you go back up to the dyno results, notice that the XE274 cammed 455 made a very high peak torque number at a relatively "low" rpm. My own engine made about 30 ft lbs less across that rpm range, but kept the torque production over 500ft lbs clear out past 5000rpm's.

What this means is that the XE274 camshaft produced quite a bit MORE cylinder pressure at peak torque, and concentrated MORE cylinder pressure in a narrower rpm range. This is, and can be a recipe for detonation with currently available pump fuel(s).

My engine lived at 10 to 1 SCR for many years, and hundreds of track runs, managing low octane fuel without the first hint of detonation anyplace. It would easily run on 87 octane fuel, we ran it continuously on 89 octane, and when torn down for inspection after years of street/strip use, showed no indications anyplace of detonation, the bearings looked like you just installed them.

Our current engine is 11 to 1 compression, and manages 89 octane fuel without any issues anyplace. Yet there isn't a week goes by that we don't see someone throw a thread up talking about the perverbial "brick wall" of 9.5 to 1 SCR on pump fuel. This immediately leads to folks jumping all over the topic with great information about lowering the SCR, then making up the lost power with a smaller/tighter LSA, "modern" camshaft to bring all the power back.

Consider this, IF this were true, and ALL the power did come back, then the cylinder pressure at every rpm would be exactly the same as the engine running MORE compression and MORE camshaft.

Reality check. The "modern" lobe profiles do NOT bring back all the power.

They do NOT make more power over the same rpm range as the larger cam having more overlap, and more off seat timing, wider LSA, etc.

The do produce more vacuum at idle, and pull the power curve into a lower rpm range, and narrow up the power curve considerably.

The result is very good "felt" power by the operator of the vehicle.

Go to the dyno and you will find that the power production at high rpm's is off considerably. No magic tricks here folks, smaller cams on tigher LSA's make less top end power, all else being equal.. ....Cliff

FWIW
 

I Track tested the same cam profile with a different LSA. The 110 LSA ran quicker then the 112 LSA.

66 bonne with a [email protected] Comp Cam and out of the box heads ran 11.50 in a 4000 lb car with a 110 LSA. ;)

Sometimes bleeding off compresion with a wider LSA will kill mid and limit the power band. But it won't ping. LOL. :D

If you have a killer set of heads requiring more rpm, then yes a wider LSA and longer duration IS needed to make the top end intake and heads work.

RE
 

I'm only playing around with 95CC heads (approx 9.38:1 compression) and a .030 455 shortblock, stock stroke and flat tops. I have run stock 7K3s with a .030 455 with several different cams (Ram air IV, Comp 292 and Summit 2802) all yielding mid to high 12 second timeslips with virtually no major tuning. Now with the ported heads and a better cam choice and carb, I'm looking for high 11s or better in a '67 Bird. Should be possible but I also want driveabilty without worrying too much about idle quality, vacuum etc. I appreciate all the info so far.

I run a 35 over 455 with 220 cfm 96 d-ports.

With the xe284 the car has gone an 11.98 at 3680.
It is a lumpy idle at 1000 rpm in gear.

This combo may have made more avg power with the xe274 but I anticipated a head change. I would think the 274 probably has better idle qualities.

Point is- you have 20 more cfm I would think about a cam this slightly bigger than the 274.
Might even consider a suitable Hyd roller to avoid the issues with flat tappets.

RE
 

I am really considering a hydraulic roller as I have been thru the wiped cam issues myself. Never used one and always wnted to try one out. Any recommendations with my setup?

I can see this thread is heading towards the same old pi$$ing contest... :doh:

I'm not even sure I wanna post any more thoughts on this??? :confused2

Everyone likes what they like,and they seem to feel everyone else should follow that logic. :-ohwell:

I dont feel that way at all myself,everyone is free to use what ever they wanna use,it's up to them in the end. ;)

No sweat off my back. :cool:

If I told ya'll what cam I'm using in the same basic combo as this one,I'm sure I'd catch all kinds of grief from some of the other posters on this thread... :heh:

But that's fine by me,I had my reasons for that choice.

:Ithink:

(BTW,could I possibly have used anymore emoticons???)

BP.

Truth be told, Cliff has reported his findings with fact.

If I were to try another hyd flat tappet I would certainly give the 60919 a try. Maybe get a little better idle quality and more avg power.

Ok,lets consider the word fact for a moment John.

From wikipedia:
A fact is a pragmatic truth, a statement that can, at least in theory, be checked and confirmed. Facts are often contrasted with opinions and beliefs, statements which are held to be true, but are not amenable to pragmatic confirmation

One persons findings are relative to that persons perception of said given set of data.

Another fella looking at the same exact findings may come to another (or completely opposite) conclusion.

Facts are established when the outcome is consistently found by all others using the same set of data.

I got a feeling were not quite at the "fact" stage with regards to this topic.

We have all read Cliff's findings on the subject,and no doubt he is accurate with much of his data,and I actually respect his contributions on these topics myself.

Contrary to what many folks here seem to think.

Cliff himself included @ times.

I got no beef with Cliff,nor with any of his preferences or testing results,go back and look at what cam I recommended here. ;)

But accepting his set of findings as "fact" does nothing to explain what others have found to be "fact" as well,those "other" facts being completely contrary to his own facts.

Both sets of "facts" cant be true,can they?

Truth be told,each individual here is depending on but one set of facts,the facts as they've seen them,that does'nt mean they're the only "facts" that count in this sorta discussion.

I can find ya'll plenty of similar (and documented) combos in the HPP shootout series or other members on here using that #60919 cam that have run nowhere near as well as Cliff's combos using that same cam have ran,so no,we cant quite say that the #60919 is a "magic" cam as a matter of "fact".

Does it run well in certain combos,yep sure does,no argument from me there.

But...

Just like the #60919,I can also find more than a few XE-274's combos out there that run extremely well too,just ask slowbird how well their old xe274 combo ran,IIRC that one got into the high 11's too,but again,there is a flip side on this cam as well,that is there are indeed combos out there that showed lackluster results with the xe-274 cam.

We could nit-pick this topic to death,and persoanlly I think we've just about done so @ this point.

Just like anything automotive performance oriented,there are success and disaster stories for just about any single given component out there,none necessarily more valid than the others,they are what they are,examples of how each worked in that specific combo,with that specific tuning.

There simply are no magic cams out there,they just dont exist.

Myself,I dont favor any one cam approach over the other,I tend to play with anything and everything as much as possible,IMHO that's how a fella learns this stuff.

One typically does'nt learn much of anything by doing the same thing over and over again,the same way time after time,all one learns from that approach is how all the "detail" items will add up to make even more gains with that combo.

But that's true with any combo,the more you work with it,the more power you'll find till you exhaust all areas of gain to be found in that combo.

A fella does'nt really learn much of anything by just going around and copying another fellas combo,as he often has no idea how to address all those "details" the first guy has found out about.

Might he achieve his goals,maybe yes,maybe no.

But this specific topic,damned if everytime it comes up,the same guys,take the same sides,and argue the same things,over and over time after time.

It's just getting really weak,,,last few "xe" threads I did'nt even bother commenting on...

I myself could care less,I'll use a 106° to 116° LSA,it really does'nt matter to me,I dont play favorites here.

I can adjust the other cam specs to get the cam pretty much where I want it regardless,now might that sacrafice some areas for other areas,yeah sure,but that's how cams work,they're all compromises.

And lets say a fella does'nt like the xe lobes...

Well,fine by me,then he should'nt use them,there are plenty other lobes out there to use.

Whatever the cam gripe,there are answers for them out there.

I dont have any beef with the xe lobes,do a search,I've recommended them in the past when the combo seemed right for them,and the one seeking advice/input wanted a simple recommendation.

I'll admit I'm not a rabid fan of xe lobes though,especially the flat hydraulic lobes,I just dont care for the noise they seem to make,if I wanted that,I'd just use a flat solid cam/lifters and call it a day.

But I dont despise them either.

Like everything,there is good and bad to be found if one looks hard enough.

:2cents:

(Was that diplomatic enough???)

Bret P.

A hot street build with ported heads, 4-speed and 3.55 gears. Intake unknown. Car weight unknown, presuambly not a pig with that year f-body. Idle quality, more avg power a must here ?

Joepapa had the crower #60211 in his '69 bird with the 406 & 4spd,and that ran pretty well,but he had more gear and compression than this 455 has.

I'd expect the weight for a '67 bird to be around 3600 lbs. or so give or take just a bit.

My "off the shelf" cam suggestion was on the conservative side no doubt at this point,mostly due to the 4spd and 3.55 gears,and the somewhat moderate compression ratio.

Now that the goal of 11's (or better) is known,,,I might make a different set of recommendations...

I really pondered this comment:

I have a few reservations.

One typically does'nt get a bunch more power from a cam without losing some degree of idle quality and driveabillity.

Honestly I dont think any cam mentioned in this thread so far will run solidly into the 11's with this sorta combo.

It's gonna take more cam,and I'd like to see more gear too.

I'd look into something like the FT hydraulic Crower #60244 now with that set of criteria.

Or a HR cam in the mid 230's intake,mid 240's exhaust @ .050".

Or possibly a FT solid like the crower #60311.

HTH.

Bret P.

Perhaps we should stick to posting facts from our own direct testing, rather than confusing everyone with a bunch of nonesense, just my 02.

Fact, we've got ONE, yes, that's ONE decent track run posted from ONE board member using an XE274 camshaft.

Fact, every single car that particular person is associated with, runs WAY faster everyone else doing the same thing. I commend them in the ability to set up their cars for excellent track runs for the combination(s) of parts.

The actual number of folks running mid to high 11's with the XE274 camshaft are rare, if not non-existant.

One of my customers with a near identical car to my own, using just about every single component that I do, aside from 3.73 gearing vs 3.42's/apprx 300lbs lighter, ran an XE274 cam in a 455 with KRE heads, and couldn't get into the 11's. He hit a brick wall at 12.0's.

He changed the cam, and nothing else, and busted DEEP into the 11's. It was a small hydraulic roller but the specs escape me. Really doesn't matter, I've had enough folks call in that were extremely UNHAPPY with that particular cam in the 455 engine, that we have avoided them like the plague.

I've also had two dyno charts sent here, and we had one posted up here a few months back, which all provided nearly the exact same results, WAY off on power and power ending quite early in the RPM range.

I think the topic is going quite well, it would go even better if folks would stick to posting usable/accurate information on the subject, without using my name specifically surrounded by a bunch of crap that is meaningless to the reader, and does nothing but further complicate and already complicated topic.

I haven't even started on the FACT that these cams can and will cause valve train instability due to the excessive seating velocity of the ramps. The last time I brought up this fact, the thread went WAY off track and got canned.

Bottom line from where I'm sitting, NOTHING impressive about that particular cam in a 455 with ported or unported iron heads that I've seen.

I also witnessed a dyno test with the XE284 cam in a 455 using 7K3 heads. Despite the very best tuning efforts, it took all day to get that engine to make 430hp, most pulls were right around 400hp, and it never did make over 500ft lbs torque anyplace. There's a FACT, as we had to wait our turn for the dyno as they pissed around most of the day trying to get that engine to make more power than a 2802 cam would have made in exactly the same application...FWIW......Cliff

PS: My purpose for putting information on this website is to help folks, not "bash" a particular line of parts. When we have information that isn't well accepted from folks who happen to use these particular parts, sorry about your luck....

Wrea - go w/ the HRoller. Man, I know it is more money - but if your like me, you'll have other stuff to worry about. Don't worry about wiping lobes.

HR cam discussions in a street 455 start w/ a cam like the CCams HR288 (I'm sure other makes have cams w/ similar specs). It has 236/242/110lsa. I "think" Dude and SD make a grind that is a little spicier and you can call either of those two ( I think the Butcher special and Old Faithful are the cams respectively). I "think" those two cams were designed for street/strip work - call those guys, great reputations and will help you optimize your combo.

I've run the HR288 in a 3700lb GTO, four speed w/ 3.42 gears. I surmise that a 67 bird w/ 3.55 gears and a four speed w/ street ported heads (I've run Butler street ported heads and that cam) would be pretty sweet and driveable.



I DON'T have the experience that these other guys posting have - but my reccs would be a performer RPM intake w/ tuned built qjet or TII, 1" spacer and a holley 4150 (again - built to your specs) and at least 1 3/4 headers (1 7/8 better) and at least 3" head pipes w/ x-pipe. The four speed will be harder to get ET's faster - the lighter you can make that car, the better. Also, lighter = less broken stuff w/ a manual tranny and easier to get traction.

GTO Lou, what times did you run with the HR288 cam?

Bret-

I knew you would take exception to my Fact comment. IF I were referring to your data not being fact based I would have quoted you.

My combo runs in the very high 11's with a head the flows 10cfm over stock. The engine was dynod and it was done by 4900. In conversations with cliff this is a typical characteristic of the xe grind.

I always wanted to know if it would run better with a 60919. I am NOT putting another HFT in this engine, roller is next.

John

I've got that cam in a street 76 TA - haven't run it in that. When it was in my 69 GTO, 474 fastest 1/8's were in the 7.6-7.7 range w/ 95-96 mph. I always left HP on the table - my MPH always predicted a better et than I actually got. Heavy gto, four speed, plus - I'm a weekender doing this for fun. My 60 foot times rarely got under 1.9 (1.86 fastest?).

OK why don't we look at an UD 288/296 that has similar specs. Bullet and Lunati still can grind them on what ever lobe sep you want, so maybe a good choice too with similar specs. I've got multiple dyno pulls in a 400 and a 455 where it doesn't lay down at 4900! Lee Atkinson's old early Bird ran mid to low 11s with it, that was not a high compression engine. So we can keep the same specs basically (231/239) and have alot of data from lots of guys including the Butlers that used that cam.

One thing I find interesting it seem the cam gets the blame for the rpm limitations and no mention of the head. Almost all the formulas for rpm peak use the head CSA or other numbers for an rpm prediction. We're asking a 215-230 cfm iron head to feed 455-470 ci and wonder why the rpm is limited?? In fact just last night was talking to a well know Pontiac "stocker" that using PORTED D ports on a 455 SS cat they were building was head limited.

FWIW one of our west Texas Pontiac guys has had good luck with the Comp XE 274 and the 284 in some pretty fast Pontiacs, but then his cars go pretty fast regardless of what he has in them.

We ran 11.8s to 11.9s with the xe274 cam in our street 400. We did put it into our 455 but the lobes went flat before we got it to the track. It seemed to work pretty good in the 455. I know it ran great in the 400.

From a old catalog, the discription for the Ultradyne 288/296 hyd flat tappet with 231/239 at .050 and ground with a 110 lobe separation, .485/.507 lift ....

"Hot street/bracket cam, 3000ss converter or 4-speed. No power brakes. Power 3000-6000."

I believe Lee's best with that cam in his first gen bird was 11.46 at 115.4 mph with a 1.53 60-ft. It was later when he switched to the Ultradyne 247/247 at .050 solid flat tappet ground with a 108 lobe separation that he ran 11.27 at 119.61 mph. It was my understanding the "bigger" solid cam was just as driveable as the smaller hyd cam. I wonder what his comment would be about "no power brakes" with the small 231/239 cam ?

Jim Butler stated the Ultradyne 276/284 (243/[email protected]) soilid flat tappet cam ground with a 110 lobe separation was good for 1.2 bhp/cid with 9.5 compression (540 hp /455cid)

My 304/312 FTH UD in a 400 ran my power brakes fine, and even the A/C with a idle solenoid! But was on a 112 LS.

I know we are in the street section but talking to the "stocker" guys they run some BIG cams, as big as alot of race guys rollers, with the stock lift-part of how they go so fast. 400 ci D port early Birds deep in the 10s and well over 120 mph! I'd almost guarantee they aren't worried about that bottom end TQ, they must have enough to launch and get those times as they have to be stock weight.

I had a .480/280 Crane in my 350Pontiac engine in my Suburban and had great power brakes! But, if it were me, i'd try bout a .500 lift/290ish duration hyd in your engine. Im running this type of cam in both my 455's(they both runnin 11 to 1) and they run like crazy up to 5400rpm. U could always advance 2-4 deg if you runnin tall gear.
Your engine will be done by then anyway no matter what cam you put in it, so you might as well build torque, not horsepower. With these cams you get both. 108LSA is in the ballpark, and these cams are absolutely streetable. Use some good oil(Rotella, Amsoil and the like) and you shouldnt have to worry bout wiped lobes if break-in procedure is good. Just my opinion....

That may be true but the lobes are square....LOL.

Remember it is not just the engine you will be trying to put into the elevens, it's the whole car. If elevens are your goal you must look at the whole picture. Before even considering a cam the car must be weighed. Lots of people on the internet seem give opinions on cams without considering weight, suspension mods, gearing (rear & trans), clutch or torque convertor, and tire size & compound. A well planned car can make a hero out of a pump gas street driver without having to have gobs of horsepower. That is the reason some 455s with a xe274 run elevens and others run high thirteens. Another very important consideration is the altitude above sea level of the dragstrip you will be racing at. Big difference between sea level tracks and those at 2000 ft. With a four speed car espescially you will find more e.t. gains with rear suspension upgrades than a cam change. For early birds, calvert racing split mono springs, caltracs, and dual adjustable shocks are the only way to go. That being said, get a custom ground hyd. roller, you will be much happier.

I agree...thats why guys should give as much info as possible. If he has everything else right( gear. coverter, suspension, exhaust, carb-intake, etc) the cam ideas will work without spending the cash for the hyd-roller. This stuff has to be in the ballpark no matter what cam he uses. Although, cam selection depends on all this info. Dont know how much gear he is running, tires, anything. My 68 bird runs 11.63/113 with a 25yr old Engle .503lift shelf cam. It would run even better if i'd go to a taller gear. I run a 4.10 with 30'' tire and go thru at 5600. Stock heads, intake and carb. It isnt that hard to go 11's in a 67-8 bird even with 3.36 gears. I ran 11.88/113.5 back in 1994 wiith 3.36 gears, 29.5 tire, 3600conv, driving power steering, fuel pump, alternator with almost the same engine. Had .540 CC solid in the car then. It Prob woulda ran better with the little Engle tho. Drove it everywhere with that combo at 10mpg.

I have a .030 over 455, just in a 400 block, and with the xe274 and 1.65s it has gone 12.17 in my bird that weighed in at 3425 right after that pass. Thats with 6x-4s that had the bowls flowed and the egr junk removed from the exhaust ports. No actual porting was done to the heads. It makes power to about 5300 rpm and idles at about 900 in gear with a decent lopey/choppy sound. Ive always ran 93 octane in it and never had a problem, it should be right at 9.5:1. The car can do a 1.69 60 ft. time but usually goes 1.74 or so on a poorly prepped track. However i have run 111+mph so I'm thinking if the car was capable of launching better the motor could pull the car into the 11s or at least 12.0s. With fully ported heads i would think going to the xe284 would be a better match for the combo mentioned along with a taller gear than a 3.55

"Remember it is not just the engine you will be trying to put into the elevens, it's the whole car."

Which is what alot of folks can't figure out, and why those stockers fly! Most guys have a shelf full of cams, convertors and multiple carbs. Tri Ys are even making a comeback!

I have an XE274 in my 455 with ported 6X heads, slightly massaged RA manifolds running into 2.5" X-pipe exhaust with Pypes pro-V mufflers and a home built (Cliff Ruggles designed) Q-Jet carb. My car managed 326 RWHP and 439 RW Torque. Nothing to write home about but for the weekend cruiser, I suppose it is OK. FWIW, I was expecting much bigger numbers but it may be the RA manifolds or the mufflers that are hindering some of the performance.

That aside, my biggest complaint and annoyance with this cam is the crappy idle. The idle is not rhythmic like you would expect. There are times where the starts to lope harder and there is a small stutter - kind of like a harmonic resonance that creeps up and then goes away. There is a new MSD distributor, new wires, plugs, etc on this motor. I have played with the idle set screws on this carb and there isn't any magic answer. I seriously think it is the cam itself that lends to the crummy idle. I am running unported vacuum with the timing set at 13 initial.

My next cam will be a Hydraulic Roller. I want better vacuum for the brakes and everyone that I know who is running a HR say that they will never go back to a flat tappet cam ever again. Piece of insurance.

"One thing I find interesting it seem the cam gets the blame for the rpm limitations and no mention of the head. Almost all the formulas for rpm peak use the head CSA or other numbers for an rpm prediction. We're asking a 215-230 cfm iron head to feed 455-470 ci and wonder why the rpm is limited??"

Skip, my smoothed over 6X-4 heads that only flowed 232cfm made peak power on KRE's dyno at 5600rpm's on a 455 engine. The cam sported 304/314 duration, and we saw no shortage in power anyplace in the rpm range, or power falling off around 5000rpm, etc.

When we installed the KRE heads peak power was still made at 5600rpm's.

When you mention Ultradyne cams in comparison to the XE lobes, keep in mind that I have NEVER mentioned that Ultradyne or any other line of camshafts experienced valve train stability issues which limited engine power production to around 4900-5200rpm's.

This is a problems specific to the XE lobes, not any one elses lobes that I know of.

The problem is DIRECTLY related to the seating velocity of the valves, which can and will cause "lifter crash" at high rpm's. The relatively heavy weight of the Pontiac valvetrain is part of the problem.

We have a few customers who do NOT have this problem, one in particular is running quite well with an XE274 camshaft in a 455 engine using stamped steel rockers and thick wall pushrods, combined with relativley light valve train components. The valvetrain geometry is also perfect. He just happened to be setting up his combo for pure stock racing, so he didn't use heavy roller rocker arms, and used stronger/lighter valvetrain components and a bit more spring pressure than is normally used with those cams.

He made excellent dyno numbers and backed them up with pretty decent track runs, FWIW. This confirms that the lobes have plenty of "area under the curve", and the lack of off seat valve timing is not holding them back as much as I have always thought.

The loss of stability in the valvetrain is the real culprit here, but we only see a snap-shot of this as most folks don't turn their 455's much past 5000rpm's with those cams anyhow, and the vast majority don't dyno the engines, or have the cars set up to run all that well at the track either.

If you are just blasting around town spinning tires when you leave the Dairy Queen, or doing burnouts once in a while from a stoplight, leaving a car show, or making nice U-Tube video's road racing around the countryside, etc, you would never know their is a problem right to start with....FWIW....Cliff

check out my chasis dyno results with the xe274 cam. expected much better numbers because the cars runs very strong. at the strip the best i ran was 13.5 @104 due to posi not working so no traction.

Billy, I think you are safe with Crower 60919 camshaft. Cliff's hard work and sharing of his findings are appreciated by many including myself. It is enough cam to go deep in the 11's and not have issues as being the "wrong cam", put it in advanced 4 degrees.. The XE CC lobes have issues..run away run away...

Do you think this holds true across the product line including rollers?

I also agree the idle is somewhat confusing at times. It sounds like it loading up, then turns rythmic.

No , I am just talking about the hydraulic variety.. I would not discount a Solid Roller Comp Grind but I would shy away from the Hyd roller XE's too..

The fact Billy has a 4 spd car... he does not need a cam the will spin the tires even more but with no topend....= SLOW... Hello! The Crower 112 LSA version of the RAIV would be a great match for a 455 4-spd with 3.55's and 240 cfm 9.3:1..broad power band :)

I would like to point out once again, that it is NOT my objective here to bad mouth a particular brand of parts. I've been following the flat XE hydraulic lobes and the results of them for many years. I even tried one quite some time ago in a 400 engine using well prepared #16 heads. I chose the XE268 cam, and was somewhat disappointed in the results. At that time, I had no idea why the power just quit around 4800rpm's. The cam idled quite well for the .050" numbers and "tight" LSA, and made decent mid-range power. The power did however, end sharply at apprx 4800rpm's. The very similiar Crower 60916 and 60243 cams we had been using pulled well past 5000rpm's in nearly identical engines.

I started following the dyno and track results with the XE cams, and noticed that with few exceptions they didn't pull well past apprx 5000rpm's, even the larger varieties.

I just sort of sat on the information for quite a while, then got some DIRECT information from another engine builder, a cam design expert, and a dyno operator who does a LOT of high performance engines.

The other engine builder built an engine using the XE flat hydraulic lobes, and it would NOT make power past apprx 5000rpms. The dyno shop he used made him aware of the fact that he sees LOTS of very similiar results with these cams. They labeled it specifically "lifter crash". I contacted a cam designer, who told me specifically that the seating velocity is simply too fast, and can and will cause troubles at high rpm's.

We continue to see dyno charts posted from folks who show us very simliar results, few make good power in the high rpms with these cams, and quite a few of their engines show sharp drops in power up around 4900-5000rpm's.

Of course there are a few exceptions to this, as I mentioned in a previous thread, so it's not 100 percent for all applications. In any case, the percentage is high enough, that we avoid these camshafts and do not recomend them.

I will also say, that for years I blamed the poor results I was seeing on the short seat timing events, or advertised seat to seat duration. I was wrong, the problems are more specifically related to instability in the valvetrain/valve bounce/lifter crash (or whatever you choose to call it), rather that the basic design of the lobes (modern/fast ramp).

I felt compelled to release the information above, although I knew the first time I did so it was NOT going to be very well recieved. We're just seeing enough problems associated with these parts that someone has to point them out. Now go ahead and shoot the messenger, if you feel the need?.......Cliff

Cliff,

I don't see that you knock a brand specifically.. I see that you are refering to just a certain product line within a brand.. I will say I was shocked when I first saw a SBC roller cam and it was ground on a cast iron core rather than billet steel...that scared the heck out of me...
PS: I still love Mellings, Summit and PAW , etc Generic cams :)

Cliff-

Is the 60919 a direct replacement for the XE hft (is the base circle the same)?

John

John, don't know the answer to that, never checked an XE cam to see what the base circle was?

I know that the Crower 60919 cam is very, very close to the original RAIV camshaft. Crower juggles the specs slightly, showing it to have 304/314 instead of 308/320 advertised. It shows the same .470" lift as the RAIV cam. The list the .050" duration at 231/240, and the cam card says is on a 113LSA, not 112 as listed on their website.

It's a very good choice for the 455 engine. I like to see 10 to 1 SCR with it, but it will work fine at lower compression ratios.

Our 455 engine made 455.4 hp with it using 232cfm 6X heads, iron intake, q-jet and stock HEI distributor. With the KRE heads it made 494hp, both engines made peak power at 5600rpm's.

At the track we went as quick as 11.64 with that cam, at 3760lbs race weight......Cliff

Good to know on the LSA , I had not bought a Crower 60919 yet but had planned on it..

So is a OEM Mellings 041, a Crane Blueprint RAIV , Edlebrock Performer RPM cam and the Crower 60919 are all the same? LOL Just kidding...

Larry, if the truth were known, the Crower, Edelbrock RPM and Melling 041 are probably the same cam from the same source. The Crane version is advertised as "computer smoothed", which reduces the seat to seat timing a bit, and takes some overlap out of it. I've known a few folks to use the Crane version, and no doubt their engines idled better than the real 041.....FWIW.....Cliff

Comp 305 Magnum?
 

Posted on another website........

If you wanna run real fast use the COMP Magnum 305H. I'm into pontiac's pretty heavy and that is the best cam I've ever run. I've tried all the factory performance grinds RAM AIR cams,HO grinds, not even close. me and my buddy Big Block build a 455 with 6X heads, Magnum 305 cam, forged pistons, factory crank & rods, high rise intake Holley 850, 400 turbo, 12 bolt 4:11, 71 LeMans ran 10.60's at 138 mph. I'm telling ya, you won't be dissapointed.

So what about this cam?

He probably left off the part about the nitrous...LOL

Cliff stated- "I contacted a cam designer, who told me specifically that the seating velocity is simply too fast, and can and will cause troubles at high rpm's."

And this from a recent magazine cam article within the subject about valvetrain inertia as a whole....

"Hopefully the mass of the valvetrain and high spring pressures allow the lifter to follow the cam all the way down the ramp. If not, the lifter will bounce, which kills the valve seat and sends harmonics that destroy the springs as well as the needles in roller lifters. This reduces the volumrtric efficiency of the engine, as the valve doesn't seat properly and robs horsepower."

You must design the entire valvetrain to work as a single system. The problem is that the weight of all the parts, the elasticity of the components, and the effects of the springs all work against the cam motion at high rpm.

I was mentioning UD cams for similar short seat duration but the same 0.050 as the crower/041. Since the XEs may have problems why not use some UD lobes?

I used one XE in my TAs original motor when I freshened it a few years back. A custom one 262/270 on a 112 LS. I was not impressed much either and never got a valve tick out of it, the seat duration was longer than Comp said even at their own lobe lift. Similar motor with a Sunnit 2801 runs better.

Here's a UD cam for you. But I'll be running it with solid roller lifters lashed at about .008".

FWIW, Stewart

I'd be willing, maybe over the winter to change cams as long as it doesn't require a pushrod change.

UD makes a HFT lobe that is nearly identical in specs to the xe 284. It would be very interesting to see the difference in idle and performance with nearly the same specs but a different mfr cam.

What are the best HFT lifters to buy, crowers with cool face?

Hey goat 2789 I remember that dyno day! I guess we are gonna be slow unless we change our cams?:)
FWIW I would prob pick a different cam next time. I kind of agree with Cliff.

I know people that like it but if you have a combo that can rev higher there are better choices out there.

My pump gas motor has an UD 296/304 239/247 @ 0.050 in it on a 112 LS, has 12" at idle.