340 Engine Shake

Alright everyone. Check this out



I started it up on the ground with the driveline back in and sure enough, the driveline sound is gone... I was going to take a quick spin around the block, but gun shy when I noticed the oil pressure gauge. To be honest, I've been so focused on the motor, Fitech settings etc, I didn't notice this before. It sure seems it is falling right when the surge happens. Thoughts??