Hi all I've just got my my first Big block chev about a week ago. Been doing some research and I don't know if it's internal or external balance. The block cast number is 4015445 so that tells me that it's 454 (7.4L) made between 1986 and 1990 the heads are 14092360 open chamber oval port correct me if I'm wrong please. Other things I need to know are did this motor come with a roller cam from the factory ? Because I was thinking of buying a Thumpr cam from Comp Cams. Also for street are oval ports Good,bad or ok ? It will be going into a 68 Camaro all out performance is not an issue just want it to sound and go like a 60's muscle car should.