1963 85 HP Mercury Needs Rings & Pistons

[Lee]

I hope this works! My grandmother has always dreamed that we could restore her 1963 Hydrodyne. I've completed the project over the past 8 months, except the Mercury outboard. 2 pistons are bad. Does anyone know where I can find the following parts because Mercury no longer makes these parts.

7291948A4 (Need 2 Pistons)
3930587A12 (Need 12 total rings)

Thank you!!!!!!!!