just purchased a 1963 340HP 409 engine with a matched set of 348 1960 #3758379 heads. Can I run those heads on the 409? Is it possible to have larger valves and pocket port them to flow better? I also have a set of 333 heads, bare: which heads would be best to use. Engine will be going into a 1962 chevy impala with a 700R4 transmission. Car is a street cruiser, not a hot rod.