Oil leak

[37 truck]

Completely rebuilt 1940 flathead, bored 20 thousand over a 239 cubic inch. Egge four ring pistons, Max 1 cam, Edelbrock slingshot with two 97's. Engine runs really strong and sounds fantastic. Has about 50 break in miles, and has started leaking oil out of the hole in the flywheel pan. I figured oil could only come from the slinger, the oil pump to cam cover, or the plug from the oil line in the block, so eliminated the oil pump to cam cover and the plug by putting a shop vac to the road draft tube, which stopped the oil flow immediately. My Dilemma is how to stop this leak without pulling the engine and changing over to a newer type rope seal. Vacuum pump, or PCV? Could it be blow by from the rings not fully seated yet?