Need some 318 info, cross-generations

Hi all.

I reently bought a 71 charger 318, on the info that it was "all original, a survivor"... Turns out I've been had. I pulled the motor with the intent to rebuild and retain, but found that the motor was cast 2-17-1977.... Happy birthday, motor.

So now I have these questions:

What exactly caused the 318 to have reduced compression ratings after 1974? Heads? Deck height? Simple gasket?

Are there anythings I need to watch out for while ordering parts, if I order on the basis that it is a 1971 Charger? Any part changes that will make me have to order for a 77-based vehicle?

Thanks,
Matt
Author: admin