[95ramairformula]

What do you all think a 455 with 6x4's (compression 9.5.1) Ram Air Exhaust manifolds, factory 72 iron 4bbl intake, 800 cfm Qjet will put out at the flywheel?

[Cliff R]

At best about 400-420hp and 490-500tq. I have a customer with the exact same set-up, with well ported 6X heads. His car is set up almost identical to mine, converter/drivetrain, weight, tires, etc. It runs 12.80-12.90's at 104-106mph.

My car with a 455, 6X-4 heads (232cfm), Crower 60919 cam, similiar drivetrain components went 12.05 @ 112mph, and made 455.4 hp/538tq on the dyno.

The only significant difference between our engines was the camshaft, same heads, intake, carburetor cfm, headers, converter, gearing and vehicle weight.......Cliff

[Schoust]

I run the same combo with the xe284h with the head flow around 230 or so and make 430hp. If I had it to do again with this head flow I would have gone one step down with the cam.

[PONTIAC LARRY]

K2802 Summit 224/234 will out run the XE268 ....and sound stock doing it

[Cliff R]

From direct observation, that is a "tiney" cam in a 454 engine. It might be simply OK down around 7.7 to about 8.5 to 1 SCR. For higher compression 455's, especially those with good flowing heads, there are a LOT better choices out there.....Cliff

[funkybird]

Cliff - what would you recommend? I have a similar 455 and was looking at a Lunati Voodoo 268/276 so I appreciate your thoughts.

[Cliff R]

MORE advertised duration if you are at least 9.5 to 1 static compression ratio. Those are "tiney" cams for a 455 engine, and move it out on a wider LSA.

We were asked to help tune a well prepared 455 a few years ago using a Comp 268 degree hydraulic roller cam. It was DONE by about 4500rpm's, and wasn't impressive anyplace for power production for the combination of parts.

Consider this, the factory RAIV camshaft has 308/320 degrees of duration on a 113.5LSA, and is a very good choice for the 455 street/strip engine with static compression ratios around 10 to 1.

Our old 455 made 455.4hp with Crowers version of that cam with 232cfm 6X heads (unported, bowl hogged with larger exhaust valves/port matched only)

It made 494hp with unported KRE 6X heads, and pushed our car to 11.64 @ 116mph.

You are NOT going to lower the SCR slightly, then come in with a "fast ramp/modern" profile cam at least 30-40 degrees SMALLER, pull it in on a "tighter" LSA, and make anywhere near as much power at any rpm. Unless you know a way around the laws of physics?

I see folks do this all the time, and as mentioned above, you end up running BARELY into the 12's, when you could have went DEEP into the 11's with a better combination of parts....FWIW......Cliff

[funkybird]

Thanks Cliff. Sounds like modern profiles are more marketing spin than strip results.

[Cliff R]

Once in a while I post my DIRECT back to back test results from a few years ago, right on the dyno using the very best flat lobes available. Then I have to listen to a bunch of flucking NONESENSE from a few individules that visit here, who don't even have a car that moves, let alone ever built an engine and made it to the dyno with it.

For the record, it's my testing, I choose the parts, did it on my nickle, and the "modern" camshaft LOST power at every rpm compared to a Crower copy of the old RAIV cam. Sorry if if the "hype" didn't work, and sorry if I chose the cam too small even though it showed a SOLID 10 degrees MORE .050" and .060" MORE lift than the cam we replaced. The dyno showed that it LOST power at every rpm, and moved peak HP producton from 5600rpm's back to 5200rpm's.

FWIW, If you want to critisize my ars again, have at it...but first take about $10,000 and build your own test engine, then another $1000 or so for a week on the dyno, then open your big fat mouth and critisize my testing.

I stay quiet about it most of the time for this reason, just too many "Monday morning quarterbacks" on these sites these days who have nothing better to do than pick folks comments apart like a black bird picking corn out of cow poop!

Sorry for the attitude, just being right UP FRONT about it, concerning some of the testing we have done. All of us are on a learning curve, and I've learned a LOT about camshafts in recent years.

My opinion (again this falls into the FWIW department), the "modern" profile, fast ramp, short seat timing, more area under the curve stuff is a lot of "hipe". The limitations imposed on the parts due to the diameter of the flat lifters is simply too severe to allow us to drop out 20-30 degrees of off seat valve movements, then make it up with fast ramp technology.

COMPLETEY DIFFERENT deal when you move up to a roller cam, they can, and will do this quite effectively, but still do NOT make tremendous power improvements over running a well chosen flat cam with high ratio rockers and Rhoad's lifters........Cliff

[PONTIAC LARRY]

Wells Said ! Cliff and Funkybird..... right there with ya....