Very close to the same issue I'm into with my 493 in the Savoy. I'm switching over to E85. I already have the carb and I'm working on the fuel pump, lines, and regulator.
It would have probably been cheaper to change the cam or pistons but the engine runs really well and doesn't leak so I'm going E85. So far I'm about $1100 into the conversion.
Good luck with your deal up

Gus beer

64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60