What major gaff did you find when you tore down the motor that prevented it from running? My experience: '65 Barracuda which had a 318 block transplanted along with the original Formula "S" AFB had a nice hole burned through one piston. Never figured out how that could have taken place. Local machine shop rebuilt the motor and it runs just fine now. 1986 Isuzu Trooper (four-cylinder 5-speed) had all four exhaust valves burned resulting in zero compression. I either did a valve job or maybe also a ring job (not sure about rings) but it ran after that. Beat up Ford Ranger pickup (forgot the year, but prior to 1995) had a busted (rubber) timing belt. Replaced it and it ran fine.