[Cliff R]

Jones cams have not faired well each time one has been installed and tested here from what I've seen, especially the 108LSA reverse pattern grind that you specifically endorsed telling the owner from overseas someplace that it was a good choice for what they were doing.....FWIW.

Bullet will push you toward tight LSA if you don't tell them what you want, and so will Comp Cams. Cam companies push tight LSA more for "bling" than anything else. Customers want a "menacing" idle quality not smooth and "boring". The problem with all that lope is that it tells us that the engine is not very efficient at idle speed and considerable "reversion" off idle and low RPM's until it starts settling in to where the cam is doing a good job of cylinder filling and cleaning up the combustion process a bit. Matters not in the big scheme of things, bling is cool and tight LSA can be made to work OK. Even so, take a look again at the dyno chart below, I've put it up here many times but it is a real test back to back with no other changes and even better I had next to NOTHING to do with any of it besides supply a carb kit, tuning parts and camshaft advice.

The engine is a 400 with a 4.25" stroker kit install, professionally ported #96 heads to 250cfm, 9.3 to 1 compression, RPM intake, Q-jet.

The engine builder owns a speed shop, dyno, flow bench and builds engines for a living. Even with vast experience with big block Chevy and Ford engines it was his first Pontiac build, so he just called Comp Cams and they recommended the XR276HR cam, 276/284, 224/230 @ .050" and 110LSA. That isn't a good choice for one of these engines as it makes a lot of cylinder pressure early in the RPM range but has been relatively popular over the years. In any case when they went to dyno the engine is pinged pretty hard before they could get past about 26 degrees total timing, which coincidentally was EXACTLY what I saw here with the last two 455's brought here for custom tuning. Of course I immediately get a call and EVERYONE right down to the guy taking out the trash at that facility is blaming the Q-jet. I had a long talk with the owner and told him that several 455's brought here to custom tune with that same cam in them were also octane sensitive and difficult to tune without detonation. I recommended a different cam but he went on to crank some timing in it and spun the rod bearings right on the dyno.

So I get another call for a cam recommendation. I had him use the older lobes (slower ramps) and duplicate the Old Faithful cam, 289/308, 236/245 @ .050" and 114 LSA with the intake installed at 110ICL. He was silent for a moment then went ahead and followed by advice.

About a week later I get another call and he sends copies of the dyno sheets shown below. He also commented that the new cam also had the engine idling better and the "shake" and "quirky" idle quality was gone. It was basically smooth now with improved throttle response and they were able to crank a LOT more timing into it without detonation. With the additional timing this certainly will improve idle quality and it was able to make quite a bit more power on the dyno as well.

I've also bought the dyno time and back to back tested three different cams quite a few years back. For those of you that throw rocks at the RAIV cam it made almost the same power as a custom ground HR cam with 284/296, 230/242@.050", 112LSA specs with .361" lobes. The RAIV cam actually made peak HP at 5600rpms and the roller was done at 5400rpms.

Over the years I haven't seen much more than dyno sims to compare camshafts. Since the 3 cam swap was done in my own 455 I went on to street and track test the HR camshaft and compare track numbers as well. Even though it only showed us 3hp/4ftlbs more torque on the dyno it was worth a solid tenth of a second and nearly 2mph at the track. The best ever run with the RAIV cam was 11.64 @ 116mph. The roller cam went 11.52 @ 118mph so there is a little more waiting for you in actual use that what you will see from the dyno testing. I suppose it's mostly from less friction and the engine revs quicker thru the RPM range more than anything else........Cliff

[slowbird]

Originally Posted by pastry_chef

I have EA Plus and the Pro version as well. Unfortunately not near accurate enough to get correct valve timing events. EA plus loves exhaust duration, LSA out to lunch - even for Chevy engines.

Builders of other many other engine families know for a fact what works. Real back-to-back dyno testing with 4 or 5 good cams through the same engine has been done many many times. Long overdue for the Pontiac community, probably won't ever happen. IMO it would shock to many and turn years of forum talk on its head.

Imagine a dyno cam shoot-out with four cams through the same engine to obtain max power within a streetable range. See where numbers really stand.
1) A "traditional" Pontiac pick, maybe 041 or something. Typical dual-pattern - wide LSA.
2) A Bullet Cams custom pick.
3) A Vizard custom pick.
4) A Jones custom pick.

Jones stuff is expensive, you buying?

[Cliff R]

The dyno time will be a LOT more than the cost of the camshafts.

Cam swaps in Pontiac engines are easy, especially if it's strapped to a dyno as you have full access to the valves covers, rockers arms and front of the engine to get the water pump and timing chain out of the way. I did it for 3 cams but it still took 2 full days of dyno rental time.

Talk is cheap with this sort of thing, building an engine and swapping 4 cams around it with dyno time for each one will be EXPENSIVE..........and highly UNLIKELY anyone will be doing any of this sort of testing anytime soon.......IMHO.......

[Steve C.]

I'll suggest if Bullet did push toward tight LSA and so did Comp Cams that could be considered positive in such testing.

And regarding #3 on the list.... "A Vizard custom pick".

Before we trash that idea right away, for interest read the entire page number 10 here:

https://www.speed-talk.com/forum/vie...5639&start=135

Some might agree a cam suggested by David might be included.


.

[Cliff R]

I've tested PLENTY of tighter LSA cams on the dyno Steve, clear down to 108LSA. The larger ones make great power, the smaller ones not so much. I wouldn't even look at putting a cam on anything tighter than a 112LSA in a 455 build until we get out past 240@ .050". As I've mentioned many times on here the biggest "turds" for 455 builds that I've been associated with, usually to help custom tune them were using smaller (short seat timing) cams on tight LSA's.

I've seen folks stick XE262 cams in them for crying out loud, then wonder why they don't make chit for power anyplace, not even decent torque numbers. Common sense should prevail there, it's a HUGE engine and a tiny cam isn't going to do well at cylinder filling anyplace, ESPECIALLY if you advance the intake valve and close it early in the cycle.....DUH?

As it relates to dyno testing, it does NOT tell us the whole story with these things. With unlimited cooling media and the fact that most dyno operators cool these engines way down before making pulls on them doesn't tell us if it will run hot/overheat/detonate on pump gas once it reaches the vehicle and gets well heat soaked.

Idle quality is NEVER as good in the vehicle as we are adding additional load to the engine from the water pump, alternator, fan, torque converter, etc. I've seen a few engines idle pretty decent on the dyno then not so well once they reach the vehicle and "dragged" down with accessories and the trans is placed in gear. For some reason folks tend to think that I don't like or use tight LSA camshafts, actually I've used a lot of them and have made as high as 750hp with them on "high" end full race builds. For my street engines I'll typically go no tighter than 112LSA, and in recent years have been getting excellent results in the big CID builds going out to 114.......Cliff

[Skip Fix]

FWIW my 455 with RAIV heads and then the 400 RAIV motors I ran in NMCA were the old UD 288/296 on a 108 ran A/C fine with both and made good power also. I thik Lee ran a similar UD in his first gen Bird for a long time also.

[Stan Weiss]

Originally Posted by Cliff R

Jones cams have not faired well each time one has been installed and tested here from what I've seen, especially the 108LSA reverse pattern grind that you specifically endorsed telling the owner from overseas someplace that it was a good choice for what they were doing.....FWIW.

Bullet will push you toward tight LSA if you don't tell them what you want, and so will Comp Cams. Cam companies push tight LSA more for "bling" than anything else. Customers want a "menacing" idle quality not smooth and "boring". The problem with all that lope is that it tells us that the engine is not very efficient at idle speed and considerable "reversion" off idle and low RPM's until it starts settling in to where the cam is doing a good job of cylinder filling and cleaning up the combustion process a bit. Matters not in the big scheme of things, bling is cool and tight LSA can be made to work OK. Even so, take a look again at the dyno chart below, I've put it up here many times but it is a real test back to back with no other changes and even better I had next to NOTHING to do with any of it besides supply a carb kit, tuning parts and camshaft advice.

The engine is a 400 with a 4.25" stroker kit install, professionally ported #96 heads to 250cfm, 9.3 to 1 compression, RPM intake, Q-jet.

The engine builder owns a speed shop, dyno, flow bench and builds engines for a living. Even with vast experience with big block Chevy and Ford engines it was his first Pontiac build, so he just called Comp Cams and they recommended the XR276HR cam, 276/284, 224/230 @ .050" and 110LSA. That isn't a good choice for one of these engines as it makes a lot of cylinder pressure early in the RPM range but has been relatively popular over the years. In any case when they went to dyno the engine is pinged pretty hard before they could get past about 26 degrees total timing, which coincidentally was EXACTLY what I saw here with the last two 455's brought here for custom tuning. Of course I immediately get a call and EVERYONE right down to the guy taking out the trash at that facility is blaming the Q-jet. I had a long talk with the owner and told him that several 455's brought here to custom tune with that same cam in them were also octane sensitive and difficult to tune without detonation. I recommended a different cam but he went on to crank some timing in it and spun the rod bearings right on the dyno.

So I get another call for a cam recommendation. I had him use the older lobes (slower ramps) and duplicate the Old Faithful cam, 289/308, 236/245 @ .050" and 114 LSA with the intake installed at 110ICL. He was silent for a moment then went ahead and followed by advice.

About a week later I get another call and he sends copies of the dyno sheets shown below. He also commented that the new cam also had the engine idling better and the "shake" and "quirky" idle quality was gone. It was basically smooth now with improved throttle response and they were able to crank a LOT more timing into it without detonation. With the additional timing this certainly will improve idle quality and it was able to make quite a bit more power on the dyno as well.

I've also bought the dyno time and back to back tested three different cams quite a few years back. For those of you that throw rocks at the RAIV cam it made almost the same power as a custom ground HR cam with 284/296, 230/242@.050", 112LSA specs with .361" lobes. The RAIV cam actually made peak HP at 5600rpms and the roller was done at 5400rpms.

Over the years I haven't seen much more than dyno sims to compare camshafts. Since the 3 cam swap was done in my own 455 I went on to street and track test the HR camshaft and compare track numbers as well. Even though it only showed us 3hp/4ftlbs more torque on the dyno it was worth a solid tenth of a second and nearly 2mph at the track. The best ever run with the RAIV cam was 11.64 @ 116mph. The roller cam went 11.52 @ 118mph so there is a little more waiting for you in actual use that what you will see from the dyno testing. I suppose it's mostly from less friction and the engine revs quicker thru the RPM range more than anything else........Cliff

Cliff,
I know you have done way more with Pontiac engines than I have. But lets look at some other numbers from the cams above. The 276 with 110 LSA has 60 degrees overlap at rated duration. Your custom 114 LSA OF has 70.5 degrees of duration at rated duration. While all cam events are different with the custom 114 LSA OF in on a 110 ICL verses the 276 cam, the greatest change is how much earlier the exhaust valve opens.

Stan

[Steve C.]

Cliff, many here are aware of the testing you have been associated with. No dispute there or the results intended here. That said, I agree it would be of interest to have back-to-back dyno testing with 4 or 5 good cams through the same engine. However as already mentioned it is very unlikely within our small community.

And like Skip, I've had two cams recommended by Harold Brookshire with 108 lobe separations that were great .... for my specific combo and intended purpose at the time, an important key. In fact if memory serves me right all three first place wins with my car at the Pontiac Southern Nationals in Dallas had a 108 LSA, but I'm certainly not going to hang my hat on that reason !


.

[Steve C.]

Lee Atkinson's 455
Ultradyne, 231/239 intake / exhaust @ .050"; advertized duration 288/296 intake/ exhaust; .526" lift intake / .550" lift exhaust; 108 LSA

https://pontiacstreetperformance.com...uild45500.html

.

[Cliff R]

I just gave you a test, no comment on it? Unless my math is wrong the custom ground OF cam I recommended made just a little bit more power than the Comp XR276HR cam, allowed more timing in the engine, idled better, and did I mention that it didn't ping on pump gas and spin the rod bearings either?

Folks ask for dyno tests, I tested 3 cams back to back, so we have some results with this sort of thing. I do agree that it's highly unlikely anyone is going to put their money where their mouth is when it comes to this topic. It's complicated, expensive, and when you get done there will be folks come on here and pick apart your testing even though they have about as much experience building and testing these engines as I spent on the crapper last week!....LOL.....

[pastry_chef]

Originally Posted by Cliff R

Jones cams have not faired well each time one has been installed and tested here from what I've seen, especially the 108LSA reverse pattern grind that you specifically endorsed telling the owner from overseas someplace that it was a good choice for what they were doing.....FWIW.

Not Jones, you are confused.

That owner tried a Crower 60919 after and his engine STILL pinged, obviously more going on there!

[pastry_chef]

Originally Posted by Stan Weiss

lets look at some other numbers from the cams above. The 276 with 110 LSA has 60 degrees overlap at rated duration. Your custom 114 LSA OF has 70.5 degrees of duration at rated duration. While all cam events are different with the custom 114 LSA OF in on a 110 ICL verses the 276 cam, the greatest change is how much earlier the exhaust valve opens.

Stan

Here is a picture that will be pretty darn accurate. Using a few hundred data points from Comp.
IMO insane to think LSA was some kind of big player there.

Funny how these guys got north of 490 HP with the same 276 cam (attached image) Almost 70 dyno pulls noted in the article.
https://www.hotrod.com/articles/hppp...e-stuska-dyno/

Tom S got 432 HP with the same 276 cam and STOCK HEADS. Drove that 9.5 compression 455 engine for thousands of miles on California gas!

Originally Posted by tom s

FYI,my 455 with a stock set of 48s,9.5 CR and a comp 276 hyd roller cam,224-230 on a 110 made 432 at 5100.Stock 69 QJ,stock unmolisted 69 intake,etc.Just a pump gas 455 RA III type build.Tom

I see facts from BS.

[pastry_chef]

Originally Posted by slowbird

Jones stuff is expensive, you buying?

Tell you what if the Pontiac community got the rest lined up.. I'll buy the Jones custom myself to donate to the dyno project.

Just need a significant group of others to throw in 20, 30, 40 bucks each. We'd need a few $K total.
Like I said, it would open eyes up.
I could bankroll the entire thing myself.. I don't believe the community deserves that.

[slowbird]

Originally Posted by Steve C.

Lee Atkinson's 455
Ultradyne, 231/239 intake / exhaust @ .050"; advertized duration 288/296 intake/ exhaust; .526" lift intake / .550" lift exhaust; 108 LSA

https://pontiacstreetperformance.com...uild45500.html

.

I ran that 239 .550 lobe (single pattern) in my firebird when i first build the 462 (20yrs ago) ls was 106, ran mid 11s. Car weight around 4000lbs with me in it

[pastry_chef]

Originally Posted by slowbird

I ran that 239 .550 lobe (single pattern) in my firebird when i first build the 462 (20yrs ago) ls was 106, ran mid 11s. Car weight around 4000lbs with me in it

Gasp! 106 LSA for a Pontiac.
How could that be.. LMAO.

[slowbird]

Originally Posted by pastry_chef

Tell you what if the Pontiac community got the rest lined up.. I'll buy the Jones custom myself to donate to the dyno project.

Just need a significant group of others to throw in 20, 30, 40 bucks each. We'd need a few $K total.
Like I said, it would open eyes up.
I could bank roll the entire thing myself.. I don't believe the community deserves that.

Im pulling the 462 out of our GP in a month or so and was going to dyno test some with it. Might be able to dyno test cams (only willing to do hyd rollers though)

[pastry_chef]

Originally Posted by slowbird

Im pulling the 462 out of our GP in a month or so and was going to dyno test some with it. Might be able to dyno test cams (only willing to do hyd rollers though)

Cool. This is the idea.
The big win IMO would be to test the "traditional" wide LSA stuff against custom that would be different in specs.
Obviously the custom cams people should believe their cam design would be an improvement.

[Steve C.]

Sort of a mirror to my thoughts, if any cam contender did push toward a tight LSA it would be considered positive in such testing. The results would then be presented.

.

[slowbird]

Originally Posted by pastry_chef

Cool. This is the idea.
The big win IMO would be to test the "traditional" wide LSA stuff against custom that would be different in specs.
Obviously the custom cams people should believe their cam design would be an improvement.

You wanting to test traditional flat tappet cams?

[pastry_chef]

Originally Posted by slowbird

You wanting to test traditional flat tappet cams?

I think roller cams may offer more insight provided the engine has decent induction and can breath.
It is common to see 500 to 520 HP - 455 engines with flat cams and around 260 CFM heads, dual plane intake. IMO too much potential being limited by heads and intake.