I need help with my 1972 351C (only people that know alot about engine please)?
Put a timing light on it and set it for 10 to 12 degrees initial timing and make sure your firing order is right. If the problem persists, you may be rounding off a lobe, remove both valve covers, bump the motor over and look for a loose push rod and/or a rocker arm that doesn't move as much as the rest.
Aussie heads have 2V runners for streetability and 4V combustion chambers for quench and BIG valves, the best of both.
Chamferring the oil return holes in the valley help with oil return. This is done during a tear down only.
The rpm range on a manifold is where it responds best, it is meant as a guide for selection against other parts.
2V heads, a 1500-6500 rpm cam and manifold, with a 750 carb will make an EASY 400hp Cleveland.