I believe my block is already .040 over bore and 3 of the cylinders had a huge ridge on them.
I did see that Hughes performance makes a stroker kit for a 318 $2000 ish
Honestly I don't believe the machine shop around here could do it with out detailed instructions on the little extras needed to do this 318/390 build.
As I read there was lots of special matching and machineing done to prep the block