I'm 80% sure it's related to fuel. I have the little fuel pressure regulator on the fuel filter and it's showing 50psi at idle and revving

Any ideas?

Fuel pressure should be something like 38psi (pump running engine OFF) and
drop to around 32psi with the engine ON and idling. If you have 50psi at idle
your engine will be running way rich and blowing black smoke.

If you have an adjustable fuel pressure regulator, turn it down some. Also make
sure the vacuum sensing hose connected to the regulator has not fallen off.

Cheers... jondee86