You mentioned that the "special" crank had something to do with the pressure. However, the motor was never without pressure and that the gauges were finally found to be incorrect (first 2) third gauge showed pressure normal.
It might have something to do with changing the gauges finally "fixed" the problem. But you said there were no restrictions. So it can't be something like Teflon tape blocking the passage.
Hmmmm... all I can think of saying is I'm glad it wasn't me
Ok lets hear it as I've got to go down and finish putting my Grand National back together...
Also the "kid" is bringing over his Big Block 66 Vette so "Dad" can find the
oil leak. Fun job, thank God I've got a lift.
Regards,