88\" to 107\" big bore conversion piston set. Incl. forged 10.5:1 CR domed 4-1/8\" bore pistons, Hastings rings, circlips, wrist pins. Requires 4-1/8\" big bore cylinders and case boring. Works with stock 4\" stroke flywheels of 88\" models. Note: Does not include any gaskets. Note: Oversizes are not available.