It really seems to be in pretty good condition. I've been working on the lower transfers tonight, can't do much else without the piston....
You should be able to widen the intake and exhaust to a full 70% of bore. You can do what you wish with the upper transfers as well. The skirts are wide and the ring locating pins towards the middle of the intake. Gasket match the cylinder base. There's room for a LOT of improvement there.