MC,
you may change the rocker arm ratio if it is possible with that motor - but watch out for coil bind at the valve springs, or the valves hitting the pistons (+ 20 hp).
You may reprogram your computer advancing your ignition curve for higher octane fuel (+ 15 to 25 hp).
Feed the intake system with cold air. That itself may present you 10 % Hp, depending on you current setup.
Nascar vehicles used to cost USD 20 000 for the car, USD 20 000 for the engine, USD 20 000 to set up the air intake system ...
Add Turbocharger(s) with Intercooler, if the engine will hold together (+ 300 hp). Or a belt driven supercharger.
How about the header / exhaust system (+ 15 hp)? Or an underdriven water pump (+ 5 hp)?
Get all-out Chevy aluminum BB with 500 + cui with 950 hp @ 6900 rpm ...
All hp-values listed are just estimated numbers!
Rick,
the dip-stick adds 7.432 hp (per DIN 70 020, Nov. 1976) @ 752.5 rpm. We tested that as well. Although, it was the candy apple red version.
Dom