[DavidNJ]

CHI has a revision of their 218 that is a 225. They also sell their own manifolds. CHI heads dominated the last small block (410) Engine Master Challenges and finished second in the first (366). Arguably (and there are lots of people who will argue) they are the best street SBF heads.

However, the Trick Flows, Edelbrocks (at least ported), and others are also very good. Most of the really trick SBF stuff (Yates, BT, CME) are race only $7000 and up heads. They, and even cast iron N1/N2 heads, require non-Windsor exhaust manifolds. Jegs sells a canted valve head that uses stock Windsor manifolds.

Most racing engines (all that I know of) use the 2.25" small Windsor main journal for less friction. They would use a 4340 or EN30B crank.

If you are planning to supercharge, you will need to go Windsor. I know of no off-the-shelf stuff to supercharge a Cleveland that will fit a Cobra. You could build a custom setup though; even using Rotrex superchargers.

Now, the bottom line. You aren't looking for that much power. A $8000 normally apirated 347 crate engine with carb or efi will meet those power levels. A blown 302 would probably be there also.