Exactly what I have is 3 small block Chevy 4 bolt main core motors. One is a total running motor without any even more than 60,000 initial miles that is out of a 72' Chevy truck - $500.00. Second, I have two partially took apart SBC 4 bolt primary motors, they were dismantled for evaluation both ran effectively and were non-smoking engines. One was a high performance built motor that I do not have specs for and the other was a rebuilt motor that ran extremely strong and was restored by a national home builder - $300.00 each or pay $600 for both and get 4 sets heads consisted of in the plan. Everything came out of 67-72' Chevy trucks. 509 9 9 absolutely no 3608.