JRS19

I just bought another project banshee and the previous owner said it had a big bore kit on it but didnt kkow what one. The engine was seized from his kid starting to change out the gaskets then decided not to finish about half way through..? Lol idk but he left the engine outside with head off completly open for 5 years. Smh i finally got the pistons free but they need new rings and i dont know what exact ones to get . Under the pistons the have markings “393” and a “w” with a circle around the w on the top of pistons it says F51G9 0.50 MM 513P2 CD i cant find them or what rings to get so plz helpppp!!!!!