So, I just bought a 1965 pontiac Tempest Custom (GTO Clone). It has a 67 YT 400 w/ 670 heads. The guy that i bought it from said it had a mild cam (of course he didn't know the specs). He did not know of anything else done to it. Hell he did not even know that it was a 67 motor until i told him. So with all that said. I know nothing about these 670 heads. What fuel do i need to run? It is a street car, daily driver. i have drove it several times already with 92 octane. But please tell me if i am wrong or if I should get new heads for the street. Thank you in advance.