My engine losses power when i hit upgrades and spits and sputters when i get on it... i've got some performance type mods on the external part of my truck... but i know that i've gotta put some on the inside... i've got an Edelbrock Intake and Carb... they sale a "Performance Power Package", but i've already got 2 of the 4 parts in the package... and i don't wanna buy a head for a 350 if it won't fit my 305... i'm gonna buy the Edelbrock Camshaft, but in search for the right heads... i'm looking at the Edelbrock 60659 that has 170cc Intake Ports and 70cc Combustion Chambers... 2.020" intake/1.600" exhaust valves. 1.460" valve springs... .575" max lift... and 3/8" Rocker studs... now i'm iffy whether it'll fit my 305, but i know external parts can swap... but i think i'm S.O.L on this one... Do i HAVE to buy the heads specific to the 305 5.0L engine? any help is much appreciated!