Help with cam selection

[koupe377]

Originally Posted by olddog

I have 236/242 duration @ 0.050 lift in a 347 cid, and it does not like to pull smoothly much below 1800 rpm. I lowered the rear end gears because of this. I cannot feel the torque drop off all the way to 6500 rpm by the seat of my pants (I'm sure it does but I do not feel it). If I ever pull my engine down, I would drop ~5 on the duration and go a little wider on the lobe separation.

What lobe separation are you running now?

Originally Posted by RICK LAKE

Also watch the tko 500 trans, if yours has all the updates, There will no problems with it. Your motor with a little work will push this trans to it's rate limits of 500/500. The torque number will be higher. Get ahold of Joe craine and let him port the intake and heads to match, than go 1 step higher than the camshaft you are looking at, BUT stay under the 5,000 rpm range. This will give you the nasty exhaust sound and still be drivible. advancing or retarding the camshaft will move the power band around also. Torque is better than HP. Rick L.

Tremec's tranny's will actually handle much more power than they are rated for. Not to mention I believe those ratings are based on a 3000lb vehicle. Cobras are much lighter and because of that the TKO can handle much more than 500ftlbs in them.

I agree you should port the heads and intake to but I would also shave them to 58cc chambers to bring the compression up from that low 9.5:1.

However, I think you should run a cam that will let you pull to 5800-6000. There's lots of power to be had up there. These cars are so light not sure why you would want to build with so much emphasis on torque. Especially when traction is already an issue. It doesn't matter how much torque you have if all you're doing is spinning your tires not going anywhere.

Originally Posted by worksalot 2

Heads are box stock fast as cast trickflow 170s (which flow number like the afr185s because of valve placement...I think) and the intake I currently have is the performer. Nothing is port matched at this time.

Sounds like a really nice combination when you get done with it. One thing to point it though is that the AFR 185's will out flow the TW 170's all day long. The 170's flow less and that's WITH Trickflow using a 4.150 bore. AFR uses a smaller 4.060 bore and yet still has more flow. Your engine is only .030 over, so you wont be getting anywhere near the 170's advertised numbers. The AFR's would be a little more accurate being the bore is closer to .030 but it still wont be the same as what they advertise

Trick Flow 170's flowed with 4.150 bore
Intake:
.400 - 233
.500 - 251
.600 - 251

AFR 185's flowed with 4.060 bore
.400 - 255
.500 - 285
.600 - 297

AFR's - more flow with a smaller bore. You can also see that from .500 - .600 the 170's pick up no airflow at all, however, the AFR's from .500 - 600 pick up 12 cfm. Anytime you're looking at flow numbers always find out what bore was used. Most manufactures use bigger bores to inflate their flow numbers. But with that said the only true way to compare two sets of heads is to flow both sets on the same flow bench at the same bore.

This is a mild motor you are building so there is no reason for the extra cost of a custom ground cam, something off the shelf will be fine. I also think you should ditch the Performer and go with the RPM of even better the RPM Airgap. More power plus the AirGaps look cool for when you pop the hood.

Also as mentioned have the heads ported a little and shave them down to 58cc, higher compression is free horsepower. You're leaving lots of torque and power on the table running the 9.5:1. Even if you don't port them, shave them.

Originally Posted by blykins

John, I have a left-over cam from Cliff Rosson's 331 SBF that I did for him several months ago. It has about 5-6 dyno pulls on it, but other than that, I ordered it brand new for his engine. It's a 228/232 duration, a little over .600" lift with a 1.7 rocker. Standard base circle, so you'd have to use link bar lifters with it. I'll make you a deal on it that you can't refuse....

John, this sounds like it would be a good cam for your combo. Personally I would run 1.6's as your heads flow no more at .600 than they do at .500. Even with 1.6's your lift will be around .565.

Not trying to step on anyone's toes just giving my thoughts on it.