New to forum and a Vintage Jet Ski

[Dogface]

A Basket case JS300A fell into my hands, all was apart and in boxes.
Fugured out where every thing went. Problem is I need to put a new piston
and Rings in it which is normal. But I may need a new Cylinder it is scored up
pretty bad.

Anyone know what the max bore specs are and where to get a new Jug if
need be.

Also I will need all the gaskets and carb kit any suggetions?

Thanks