On a side note, and speaking of cheating lol, I ordered a Chinese 300 kit (256.95 loonies to my door and 6 days delivery). It's not bad. Look for the one that has 299 stamped on the cylinder.
Piston is lower compression (good cause even the 250 has given me some knocks during testing with our fuel up here) , 8 gr lighter that OEM 300 but pin just about equals it out, same taper, fit is 1.9 thou. Rings good quality with good gap. Barrel casting is a little less finished externally but structurally sound and equal to OEM in dimensions. Machining on base is excellent, head surface has a bit of light milling chatter (probably fine but I lapped it anyway), honing is a little rough looking at it magnified, they should add to coolant flow to help with build up. Steaming hot water and soap wash is needed to get the bits out.
Gaskets are a no go (get OEM, work perfect). Besides fit a bit off, two coolant holes in the head gasket are punched out wrong and would cause an overheat due to restriction. Too bad because the quality and material would of been fine.
All in all a darn good deal for up here.

The big stuff looks good IMO from a couple of decades in the biz. Gaskets included should be inspected. Mine were not punched correctly for coolant passages and went OEM.

After I put the circlips in my fingers I decided on OEM (kinda soft and OEM fits).
And,,, the final need-to-modify was the lower cam chain tensioner. Everything fits and is in the correct place but they stopped machining the internal relief 3mm short. So file, hacksaw or use the lathe to shorten the spring holding bolt 4mm shorter.