Bad oil leak and no oil presure

1983 c-10 pick-up 350 engine. Oil leaks out real fast. About 4 qts. in 30 secons. All over drive way. Oil gage shows no presure at all. Some oil is on top of motor which makes me supect it,s comming from the dis. shaf hole. What would do that. The oil is getting out of pan but it gos on the drive way before it's gets in the engine. Never seen anything like that before. I look around the filter, it's looks dry. I think if it was the rear main seal, it would still have oil presure, I guess. If the pump stop working, It would seem the oil would stay in the pan. Have not had a chance to look at it real close yet. Just figured I though this one out there and see if anyone had an idea. Thanks, John.

Hmm, mabey the oil pressure gauge line is'nt hooked up at the rear of the engine, would explain both symptoms.

I had one of those break when I was in the parking lot at work. Thank God I was at work I went in and got a pipe plug and put it in the hole where the gauge fitting went in. In less then a couple of seconds I had 3 quarts on the ground.

That was it. The little copper tude had come off. It,s suprizing how much oil can come thought that little hole. No motor damage I don,t think. Simple things can happen real fast. Thanks, John.