I opened the engine up to do the rings before I put it back in the car but found the inside was not as perfect as I had thought. The biggest problem is that there is a gouge in cylinder wall #4 from rust. It looks like the engine blew a head gasket, leaked water into the cylinder, was parked in the junk yard for a couple of years, transplanted into the MG with a new gasket then driven many years after. Either cylinder #4 will have to bored out and have a sleeve fitted to return it to stock dimensions (that's my first preference) or all four cylinders will have to be bored out and fitted with larger pistons (very expensive). It also turns out that I have a flat cam shaft that may or may not be able to be reground. As of right now, I'm on the more-difficult-than-I-thought search for internal parts.