Pull the pan and check for cracked or broken pickup. That pickup may be living in a different space right now. I've been there. It could also be the root of that obstruction or metallic noise you speak of. Others here have suggested that also. These pickups will crack in the pipethreads, especially if they are long, reused a few times, overtightened, or the pan bottoming out on the road/track surface.If the oil was highly contaminated with gas, as you report, it would probably be much harder to reprime after a period of shutdown. I had an old big block Dart race car. I bottomed it out on a deep Milodon oil pan. It didn't look bad but after I pulled the pan the pickup FELL OFF when I bumped it with my hand. Lucky I shut it off early. It didn't hurt the crank or bearings. You're lower end has been "gas washed" and won't prime. I suggest you don't keep trying to rotate it over. Nothing good will come of it. Good luck here. Bill