Better breathing, from the camshaft change, and a good balance job, tighter bearing clearances, etc., will allow the engine to make higher RPM's, and stay together there. It's still putting a little more stress on the engine, which might shorten its practical lifespan. The 350 round track engines I build produce 600 HP in race trim, and wind up to 7,000 RPM or more, but they're worn out in less than 1,000 miles of running those speeds.
A taller gear, and lower RPM is a better choice for a street machine.
Jerry
