MEP803A Blow By

I purchased a MEP803A from Gov Planet non running. Easy fix just a wiring repair. Unfortunately it has a lot of blow by. I tried ATF in the crank case and in the fuel, no results. I pulled the cylinder head and the head gasket does not show any signs of damage. Pistons look good with no noticeable cracks. Any suggestions?

I am willing to tear the engine all the way down and replace the rings, where can I find a complete gasket kit and piston rings? One stop kit?

Thx !