How about J C Whitney's engine overhaul pellets? You put a pellet in each spark plug hole and dumped a can of the magic ring repair into the crankcase. "Recoats the pistons with new metal" !
TM, I actually used the 'overhaul pellets' in my '63 Pontiac Catalina engine. Had a 389, but only one deuce (Rochester two-barrel carb). Aside from the fact that she drank a quart of oil a month, she ran great. Even though Lee Petty endorsed this product, the pellets and the 'magic ring repair' fluid were unsuccessful in sealing my Cat's rings.
I loved that car, wish I still had her. Very easy to work on.