If you put a small ball of clay on the aircleaner top on the driver's side, it will tell you if the engine torques over enough to hit the hood, and witness marks on an intake manifold where a pushrod rubs are common with aluminum replacement intakes. Just grind out the witness marks if there are any, with a small carbide burr, and reinstall the manifold with new gaskets. For anything less than .600" lift on a camshaft, the factory adjustable style rockers are more than adequate for a street engine. I raced a factory ford adjustable rocker arm setup for years without a single failure. Joe-JDC.
