[JLMounce]

You're 100% positive it's the rear main seal and not the pan gasket? The rear corners of the pan as well as the half moon cutout below the rear main is notorious for leaking. The factory pan doesn't help this any because there's no ridge to keep oil from climbing the rear wall up towards both the rear main seal and the pan gasket. This is why it continues to leak. Even moderate throttle application and moderate acceleration will see a wall of oil climb the back wall of the pan and seep into the gasket area.

I had the same issue with my 455 until I replaced the pan. It would drip, sometimes for days from a spot that led me to believe it was a rear main leak. When I had the engine out to replace the pan, the rear main was dry, but it was leaking from both rear corners of the pan and significantly around the half moon cutout for the rear main cap.

I opted for the 1 piece BOP pan gasket and spent a good amount of time with a ball peen hammer making sure the pan was flat. Even though the pan was new, the rear corners needed some massaging to get them flat and several of the bolt holes were concave and needed flattening. I then used a small dab of gray RTV at the front corners where the pan meets the timing cover, at the corners of the rear main cap and a light smear on both the rear main cap and that portion of the pan itself. I let the RTV set for a couple minutes, then bolted the pan up, making sure the areas that received a dab of RTV had a tiny pit smoosh out from the corners, indicating it had sealed those angles.

In my case, the engine went back in the car a couple days later, but I would wait a minimum of 24 hours to let the RTV set before putting any oil in the pan.

Also, make sure you do not over tighten the pan. It can be tempting to wrench down on this stuff in hopes of sealing it, but that bends the pan and actually pulls the rails off of the gasket surface, creating areas that can leak.

None of this matters of course if it is actually the rear main leaking. My point was just to illustrate that leaks on the pan itself can present as a rear main leak. Even leaks at the front of the pan. Because the engine is typically angled downward, plus the direction the car travels, leaks near the timing cover can travel along the crevice between the pan and engine towards the back wall of the engine where it will then creep down the back of the pan, around the transmission bellhousing, on to the starter and cause drips in those locations. You can spend a lot of time chasing oil leaks at the back of the engine when they are actually at the front!