T remember seeing in a hot rod magaine one time.About a guy had a falcon. He took a sic cylinder,took two v-5 heads cut the into--mated them up and was getting around 500hp. I do not remember whick v-8 heads.But I think it was a 351--I do not remember whether it was a windsor,cleveland or which. And the guy was a machinest ,so it took some knowledge in his field .A '78 is an awful lot heavier than an '83, The general concensus is that a 300 is not a good swap for a '78, it has to work too hard and the mileage gains are lost. On the other hand, I've never tried it and you can build up a 300 quite nicely if you know how so I would be really interested to see how it works out.