Help diagnosing oil leak(s) and troubleshooting

[SkidmoreGarage]

I have a 67 with the original 327 (with rear crank vent tube and sealed valve covers), and it is a leaky mess that is only unliveable when it's running. It leaks from the rear (through the bell housing weep hole), the front (the front crank seal), the sides (valve covers), and the bottom (pan seal). I replaced the valve cover seals and resealed the intake, and those appear to not be leaking as much, but the total amount seems to be the same.

This has been happening for a long time based on the amount of oil and dirt caked under the truck and on the engine (1" thick in some areas). When its parked it forms hanging drips but is generally not that bad. I put a drip pan under it. However, when it runs, in about 10 minutes of idling, it's enough to have streaks running down the front cross member, and puddles on the ground.

Now to the point, I think I have a crankcase pressure problem, but I wanted to check with those who have more experience. Does this sound accurate? Do the rear vent tubes get clogged? Is there any improvements or ways to test for excess pressure in these old 327s? Or, is it common and I just need to start replacing seals?