Looking for an answer to what might be happening. I’ll start off by saying it’s a 1968 289 motor and a c-4 trans. Car was a runner with a few drops of oil before car was parked and stripped down to be restored. The motor was completely overhauled at a machine shop and all that was added above stock was a very mild cam. Transmission was sent out and completely overhauled and a new torque converter was added. Running gear was installed into car and car has been completed. So after was run around the street a couple times it blows oil out the rear seal and leaks bad. Dropped oil pan and double checked seal and it was okay and changed it anyways. Put back together with new seal and gaskets and run till warm and as soon as you put it in gear and drive it it blows through again. Repeated again and same results. Took it to a shop and twice with the same results. I will help eliminate answers by saying that flexplate bolts were thread sealed, seal is in right way and it’s not from top of motor. Crank endplay was around 4 thousand and yes the breathers pcv valve are are working. Even changed back to stock valve covers to eliminate anything that was added. So then purchased another motor that was rebuilt and it never leaked before it was pulled and bairings endplay etc all were fine switch motors out and as soon as the car drove about 10 blocks it puked oil out in the same way. Talked to lots of experienced long term mechanics and we all are stump. Have to find someone who’s gone through this problem to help find what direction to go. If I don’t find the problem I’ll be cutting this car up and installing a Heidts front end and putting Chevy running gear in this thing to get away from this issue. Shame to do it but I don’t have time to play with this problem everyday and patience are wearing thin because everything was completely brand new on this car after restoration. Thanks in advance. Attached is a pic of streaks left after going back and forth twice. As you see it’s not a little leak.