A performer RPM 318 port size, and a cam change, with a set of good manifolds or cheap headers, and you will exceed that number, as long as the engine is in good shape now.
Cool, very cool. The engine had a complete rebuild and only has about 10,000 miles or so on the rebuild. The heads were ported, an RV camshaft type grind was installed with a Thermoquad 650 on top. I kept the stock manifolds but did install a complete dual exhaust with Dynomax Super Turbo's and a crossover pipe. I ask this question because I simply want more power out of this motor.