[RR67GTO]

OK, it started out buying everything for my 455 rebuild at one catalog who said I should use a 270H Comp cam. Heads are 6X-4 converted to bog valve, new ARP studs, Comp 995 springs and roller tip rockers 1.5s. Then, Comp said to send them back the cam it was not right for my engine and sent the XE 268H to me. Now, I am reading in Jim Hands book and looking at other engines where the Comp XE 274H is used alot.

Question: Before I install this new engine I can swap to the XE 274H like I see so much of. Keep the XE 268H I have (No Want A wuss engine) Or buy something else. Also, heads were never ported, just cleaned a little. Pull the heads and send to Spots for port work is an idea also. Engine was going in a first Gen Bird but now a 66 Le Mans. And my point being? Simple, before I install the engine I want a good Cam that will produce enough Vaccumn to supply brake booster. And, sound tough and run strong on a street engine. Carb for now anyway is sitting in a box and is a BG Speed Demon 750, with an RPM Performer Intake, and headers yet to be decided maybe using the RA ones by Company Who makes the nice ones. Or, Maybe DOug's. So Come one ya guy's you've helped for all the other stuf I had questions about. It's sure was a good way to learn that next time I'm ahead having someone good build it from the cround up for me. Nope, I can't do it myself because I'm blind and will be driving the car in really wide open spaces only. But, driving it hard. Thanks, and choices for the best Cam will win my vote and order it in the next few days. I, listen, debate, listen more, and then order now that I have gone through this. By the way, never listen to someone who's a salesman but not a user for the thing's they sell. < Mike >

[shaker455]

Mike, (runningbwdog)

Here's what I got with just the info you supplied as I could not find any other info on your # 15 heads w/ 1.96 intake valves...kinda small and big exhaust valve 1.770:

RPM scale starts at 1500rpm and ends at 5500rpm

Hp Tq
115 403
166 435
213 447
262 459
309 464
333 437
341 398
324 341
285 273

Jeff

[RR67GTO]

Thank you very much for the numbers. It looks like the 274 would be worth the extra time. And, if I had the heads ported and done well it should put me in the 400 HP range which is not bad for an old guy like myself.

I'm also happy now that I decided to have the valves changed to 211 x 177 because I'd be looking at doing a complete new set of heads after learning more that I knew back then. Again, thank you very much. < Mike in Oregon >

[shaker455]

Chris,
I don't have the 284 myself but I have run it on two desktop dyno programs and believe it or not the numbers are pretty dissapointing.

That's why I recomended the Crane instead.

Jeff

[455earlybird]

I'm keeping it under a 400 hood with a drop base and 3" filter but would like to do ram air setup may have to get a tall 400 hood need somone with experience with this stuff (ram air). Also really need to know what headers are best I have been looking at Doug's headers. Also are there any resonable aluminum radiators out there.

[shaker455]

Chris,
I got your email...would you like me to post the dyno results of your engine?
Jeff

[shaker455]

Don't bother,
I'm just going to have to print off your info and decode it for a loss of proper words...LOL

But I see some of the numbers I need there just not in the right order and it look like they did not use a standard lift number like .100"-.150-.200 etc

looks like they went .105-.211 etc and it look like the total cfm list is your flow....ripping my hair out now!...LOL..I'll get it for you

[runningbwdog]

Hi,
Great, I'll be looking forward to it.
Thanks,
Mike

[shaker455]

what # heads do you have?

[455earlybird]

Thanks for the info what type of rubber are your 255/60-15's what kind of car and what kind of times do you run with it. Have a great T-Day and again thanks for taking time from your holiday to run my numbers. I hope I can get answers to some of my other issues. Sorry I don't have much input to offer I'm just learning about this stuff myself.

[Formula8]

Desktop dyno is a great tool but needs to be used precisely for best results.

For example, induction flow is not neccessarily equal to carb CFM. It is a measurement of everything from the cylinder head's intake port to the air cleaner. This number becomes more important with larger displacement engines. Jim Hand's book contains some measurements of the percentage losses involved with particular intake manifolds.

Also, the compression calculator is pretty slick but you need to know many specifications to get it right other than to just plug in 10.5:1 or whatever.

My biggest issue is the lifter type menue which extrapolates the shape of the cam lobe based on assumptions made about the type of cam selected. With cams like comp's XE series and Ultradyne around, can the lift rate on those be assumed to be the same as those used on the O41 cam??

What I would like to see with these vendor's who make recommendations and sell all of these cams, step to the plate and put these cams under the dial indicator and give us cam specs every .050 and host them on this site in a data base. Everyone would be able to compare and make decisions based on complete information.

[shaker455]

455earlybird,

The flow # are good but I need more info...sorry

whats the lift on the cam and the intake centerline?...comp is usally 106

And you first posted 230/236 then you posted 230/240?...is 230/240 right?

[shaker455]

Okay,
You at w/.510/.520 lift 230/236
Hp 497@5500
Tq 539@4000

[loren]

I'm lost All I know is whats on that flow sheet I'm not to good at all this stuff yetI will have to get some help to find this out.

[455earlybird]

Mine is a 67 f-bird 400 clone had a small block Chevy but I am attempting to repair this major malfunction with this 455 setup The car was originally Mariner blue and now is a green that appears blue at times Like I said it nas a 3.55 posi and will have a turbo 400 I am building to go behind the 455 I would also like to make the hood work as a passive type ram air (no solonoids just open at all times) will need to figure a way to get home when I get stuck out in the rain though as this is a street driven car will not attempt to drive in bad weather but around here you never know. I also will have height problems with the 400 hood and a RPM manifold in getting room for the ram air setup don't know if there's a way might look into an aftermarket tall 400 hood. I know the rpm will fit I have seen it done but not with ram air.

[shaker455]

Sorry Lee,
Yes your right...I blew right over that..
thanks.

[455earlybird]

What are you doing wasting time on the outside I thought you polished the runners to improve flow or something. Show won't make it go LOL. Chrome won't get you home LOL. The rubber sounds good does it really hook up well. Got to go eat turkey with Mom and the wife and kids. Again thanks for the help. Have a great holiday.

[shaker455]

Sure, I'll post it next

[LouisianaGuy]

I am running the XE 274 in my 455 powered 4000 Lb 1977 TA. The cam produces good vac. And has nice Idle at 800 RPM. I can idle it even lower but idle gets a little rough in gear. Power is good from off idle to about 5500 rpm's. My engine is only running about 8.5-1 Compression, and I really like the cam. I am planning a head swap to get compression up to 10.0-1 and adding some better head flow numbers. Im really wondering how much more power I am going to be making by adding 1.5 more points of compression and some good flowing heads. Im just curious how the cam will perform with the added compression seeing as how its designed to function well with low compression. I may have a used XE 274 in a few months, If i decide that i would be better served with a larger cam due to the compression and head flow. Any one out there running a 4000lb car with an XE274 in a 10-1 compression 455??? If so what kinda times you putting down.
My TA ran 13.26@101 mph last time out, with fuel and timing issues, but pulled a 1.82 60' which isnt too bad for a 4000lb sled from what I understand. Should be in the 12s next time i hit the track, since i have corrected the fuel and timing issues.
Mike

[shaker455]

Formula8,
Yes I know what your saying, I have 2 dyno programs, Dyno sim and engine anaylzer, they serve as a goo reffreance not as an exact number.

Okay 455early your next