Place in Melbourne done once and no problem. Place in Qld is much cheaper, however it came off twice and the second time destroyed the piston, so cheaper to pay more the first time in Melbourne than twice plus piston.
John Hill in the UK does alloy cyls and Nicasil bores to your piston size. It's more expensive to machine and have bores done here. A JE forged piston can run .002" mine are .0025". I've not tried the 76mm A65-70 pistons EdV does from JE, Just 79.5 and 80mm B44. They work great with the long stroke because the skirts are short. They really need longer rods. I had a taller alloy block cast but never used it.
This is a sketch of the XR750 port. So I'm trying to improve the bottom turn and make everything smooth. And stop break aways and turbulence, the turbulence I think it needs is entering the cylinder and its what it is.