Got a buddy doin a 350 conversion in his lanc cruiser. He`s installing 1977 350 from a federal eq surburban auto. It gonna be changer to a stick but he needs to get a flywheel for it. Were 1977 350s internally balanced? He found a 168 tooth 11" flywheel from a old chevy pu he was gonna use.

 

I thought just about all small blocks were internally balanced except for the 400's and your some of your strokers. To answer your question, yes they were internally balanced. You can always tell for sure though by seeing if there are weights on the flywheel.
Don't forget your loc-tite and 65 ft-pounds on install. Good luck, cumminsboy

 

Thanks, After researching it some I learned 86 back are internally balanced engines and the new stuff is externally balanced.