Oil pressure drops to 0

I’ve finally gotten my car on the road and have been driving it everywhere for the past month. Today I fired up the 440 and was letting it warm up before I started driving it as I always do. The oil pressure when cold is usually at 70psi and when it’s at running temperature it’s usually around 30.
Well today, I start it, oil pressure goes up to 70, then starts dropping fast. I immediately shut it down and checked to see if my oil line had popped off. It had a small leak to I put some thread tape on it and fired the car back up. This time the oil only went to 60psi then dropped down to 0 almost immediately. The car has 6qts of fresh VR1 10-30 oil in it.
Could this be a faulty gauge? Or am I going to have to pull the engine AGAIN?