I just recently had the rear main seal and oil pan gaskets replaced. The majority of the oil leaks appear to have disappeared. I still have a leak that I cannot pinpoint. It shows up with oil drips underneath the car on the oil and tran pans. After running for about 15 minutes you can oil burning and see smoke coming out the rear. It is on the passenger side exhaust pipe. Both the trans and oil levels are full. Would a AC leak near the expansion valve cause this? It is a 396-325 with TH400 with stock AC if that helps.

GET A MIRROR, CHECK THE BACK OF THE INTAKE MANIFOLD WHERE IT MEETS THE BLOCK. I ALSO HAD A DISTRIBUTOR BASE GASKET DO THIS TO ME. CHASING OIL LEAKS, SUCK, BUT NOTHING LIKE HAVING THEM ALL CLEANED UP. GOOD LUCK.

I agree with 1 Black Harley, Check the back of the intake. I had a leak there and it can make quite a mess. As far as the oil level goes it dose'nt take much oil but one drop to make a big mess under the car. So you may not notice a drop in levels on the stick.