Back in the mid 80' s when we were running the offset ground 360 crank 2.00 inch journal 6.00 rod 355 piston engines I ran a 4.100 bore 340 block on one engine the other was a 4.100 bore 72 360 block both had oval port w-2's by Keith Dorton both blocks lived they had the same venolia gas ported...
Rtv is the only thing I have used for the last 25 years. I have had to do it over again if I didn't get enough gear oil out of the third member and it ran down and got into the rtv. Mop out as much as you can put it in quickly shove it all the way and have some nuts ready to run all the way down.
Not sure what your using for a pump and pick up. I had the same problem 20 plus years ago. I was using a milodon pan with a swinging pick up. The type where you have to put their longer gears in your pump and use their pick up. I used a new high volume pump. Zero oil pressure when priming...
Sent you a pm with a cell # If you still have the car ring us up. If you didn't get the pm I'll send it again. I'll get directions hook up the trailer and come see the car.