Rear oil leak

I've removed the oil pan and also replaced the rear main with the engine in on my 63 dart. It is a 360. You have to remove the centerlink to drop the pan. The rear main is exposed once the pan is gone. I believe you have to remove the rear main cap and then the upper half of the seal can be pushed out. You may have to loosen one or two bearing caps to relieve the tension on the upper half of the seal. Be careful putting the new one in because it's easy to cut the rubber as it's going in.