Join Date: Feb 2002
Location: N.W. Washington
Re: High RPM - Which Platform
It's really all in the valvetrain, regardless of motor size. A soundly built bottom end and decent heads and it will be a blast to drive.
If you want a 302 just because, cool, I'd do it. Otherwise maybe bump the inches up a bit, like a 3.25 stroke (ie 327). You won't need anything magic for a bottom end, just decent parts and assembled correctly.
Then get a good set of heads, don't bother with old factory castings unless that's what you want to do. A decent set of aluminum heads, and I would spend the money on your valvetrain. The cost of shaft rockers makes it the only way to go, and you won't have issues there.
If you run a big intake valve Ti is really nice, but for 8k not absolutely mandatory with a smaller valve, like maybe 2.05 and less? (Talk to a cylinder head guy). With a 4.00 bore you'll be limited anyway. The springs are important (based on cam) and run a lightweight steel retainer, they are more durable than Ti and nearly as light.
Contact a good cam designer for a cam, the right cam can make lots of power and not destroy valve parts. Worth the money for sure.
Want ideas on other options? It's not the easiest or cheapest (though not stupid expensive either), try using SB2.2 heads, and build something in the 350" range, large bore short stroke. I just did this, I have a 354" SB2.2 in my Camaro, 3.25" stroke, 4.155" bore. It runs on pump gas (big dish) and screams. Makes quite a bit of power too.
I have been driving it around a lot getting the feel of it and it really cruises easily, slightly rough off idle but nice and smooth at cruise, and wicked under full throttle. The cam is designed to shift at 7800-8000, and it's all I can do to get the shift off before the limiter (automatic too..) It's a blast.
Just remember running it up to 8k and making power to 8k are two different things.
1968 rs with an old school 354" SB2.2 pump gas motor.
Repetition does not transform a lie into a truth.
Franklin D. Roosevelt