I just went through this horror show.... I had to remove the headers and motor mounts and hoist the engine up as high as it could go to get enough clearance to get the pan out..... I had a pretty bad leak and I used a gasket kit for a late model magnum engine and I have a 70 318 block.
I replaced the rear main seal with the correct seal with the "ears" and it seems to be doing alot better but I did notice some oil leaking from the right angle oil filter adapter. I am going to get rid of it hope that solves all my oil leaks.... here is a pic of the 2 different seals...
TBF