Hi i have a 66 390 that i have rebuilt to put in my 66 comet i filled up the engine wih oil befor i put the engine in the car, as we had the engine up on the cherry picker with the the engine tilted back we noticed that we had a little oil on the flexplate running down , is the rear main seal leaking ? as i put it in new, i may have put it in wrong by mistake ?
Thanks
Mike

If you determine the seal is installed in the correct direction, check to see if the seal lip got turned inside out and that the garter spring is not missing (assuming you used a modern one-piece seal and not a two-piece rope seal). The seal lip is supposed to face inboard so crankcase pressure expands it and helps to seal it. If it is turned so the lip is visible and laying on the seal surface of the hub toward you, it is incorrect. A quick, easy test is to seal the engine oil cavity openings and introduce no more than 4-5 PSI pressure into the crankcase through the dipstick hole and check the seal for leaks using soapy water or Snoop.

Good luck.

DMS