[3 goats]

I have a 66 GTO Tripower 4 sp with PHS documentation. It has a 66 block which has a date stamp after its December 65 build date so obviously not original. Heads and tri power are wrong too. Its in good shape runs well and has an older restoration including a nice albeit non-original (not even a pontiac color) paint job. I wouldn't mind investing in a proper restoration but would like to secure a proper (WS?) block, heads and tri-power set up. My understanding is that as a 66 there are no vin stamps on the engine. Problem is that 66 block is different from a 65 (if my research is correct) and therefore I have a short window of production from which to find a legit block (august 65 or whenever they did the year changeovers then) up thru November. Not looking to hoodwink anyone but just assume do this the right way if im going to do it at all.

Any suggestions on where to look for proper date coded block?