[tjs44]

303 heads are very simular to the 400s,smaller unmachined chambers,takes a long reach plug and usually have smog ports in the exhaust.The block is way diff on the short deck,has a filled in lifter area like a SBC,has the oil filter diff.The 400 exhaust wont fit on a short deck 303 setup as the pass side will hit the filter.Im sure the 303 version will fit on a 400 setup.Remember there were 2 diff 303 setup,std deck with a long rod and the short deck.The short deck has 2 1/2 mains and was WAY more competetive but because they only made 25 of them,they were not allowed to compete.The std. deck 303 was a dog.Tom