Leak Down Findings
I pulled one of the heads off the 340.
The cylinders are as smooth as glass. So that explains the leakage past the rings.
At one time the engine must have spit out 2 of the push rods, one on each side, as there is marks on the roller rockers. They appear to be fine, as the damage is not to close to the adjuster.
Next I need to pull the valves out of the head and see what's up there. It appears the valves have been replaced with some LARGER ones, but it looks like the ports are untouched.
Another thing I noticed when I had the carb off but the intake still on is how much of the head I could see looking down the plenum. Boy does that need to be fixed. There is at least an 1/8" lip I can see. I'll have to get out the grinder and match these ports.to the intake.