2.5 L engine oil leak

Got another problem with my 91 Grand Am with 2.5L engine. I got an engine out of the junkyard and everything looked ok. It had been washed off and I could see no leak problems. When I started it and it got up to operating temperature, it had a consistent drip from the back of the oil pan. I figured I'd been dumb trying to save a buck and not just installing a new rear main seal when I had the chance, so pulled it out and installed one, and as a precaution, pulled off the plate covering the back of the camshaft, and made a thin paper seal when I could not find one, and dumped the engine back in. I cranked it up and it still leaked. I then really got to looking at it while it was running and really could not see the oil drip coming from where I thought it would be. I took a chance and pulled the pan, found a suspect place on it, cleaned it up, put RTV Blue on it and put it back together. I cranked it up the next day and thought I had solved the problem as it did not leak idling in the garage or driving around town. A few days later we went out of town and found it left a spots and got the underside wet with oil. After driving it about 1000 miles so far, it looks to have leaked a half quart of oil and only does so when driving at highway speeds. Again I can't really see exactly where it is coming from except the rear area of the engine. So finally, here's my questions, 1). What is anyone's best guess/probability of where it is leaking from? 2.) The camplate looked to be sealed originally with something that looked like a thin rubber gasket like that on a Mason jar lid. Did I screw up by making a paper gasket? Any ideas would be greatly appreciated! I don't really want to pull the engine again unless got a good idea. thanks everyone for the help in advance!

You should consider re-posting in the Grand Am forum. Some sharp guys over there to help you.






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Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

check the end of the crank for a groove worn in it by the crank seal. IF your engine is high mileage, it could have a groove worn in the crank which will not allow for proper sealing. If your engine is of a one-piece rear main seal design, Fel-pro or Victor probably make a repair sleeve.