Damn oil leak, Rear main??

Hey guys, I've had this little small block in and out many times with various combos and rebuilds and along the way I've never had an oil leak that's acted like this one so maybe you could help me out.
This is bar far the worst oil leak I've had, shut off the engine and got the dreaded drops coming from the back upper of the pan. "f**k I guess the engine had to come out" but before I pulled the engine I figured I would investigate. Seeing how this new engine/combo just went in at the start of summer I'm not really to motivated to yank it.
Got under the car and cleaned up everything removing any oil mess since this leak happens to get onto the flex plate and spatter everywhere.
With it all clean, I start the car and wait and look. Nothing. Dry. Zero leaks. Let the car idle and get up to temp. After 30 mins of run time I rev the engine a couple times. Under the car still nothing. Dry.
I shut the engine down, get under the car and it instantly starts coming out at a pretty good pace.
Hmmmm, rear main seal???
Anyone had a similar leak.
I think I have an idea what's going on , but want to get the wisdom from you guys first. Lol
Added a photo of the leak and new combo for ya guys too.

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