[AL in NY]

To get more horsepower you need to get more air/fuel mixture into the engine with less restrictions. The best way is to open up the intake valves. Putting big carburetors and manifolds on will help somewhat, but the intake flow is still restricted by the 1.5 inch intake valves. If your thinking about more performance and you're building a new engine, invest in 1.75 inch intake valves, you won't be disappointed.