Maxreilly

First time posting on a forum sorry if I did it wrong.....
I need some advice on a BBC 396. My cousins picked up a 1971 El Co with a 396 that ran well but had a bad body. After letting the youngest one take it out the next day, it started to have problems. The car would die randomly when coming to a stop, not sputter but just die and it has no oil pressure and ticks badly at idle. I set the valves but it still ticks (probably because of the no oil pressure at idle) and swapped a carburetor off a 1971 Cutlass that runs great to see if the car stopped dying when I stopped. The car still dies 80% of the time when I come to a stop. The gauge reads 0 PSI it idle but 35 PSI warm when I bring up the RPMs and the ticking also stops so I don’t think it’s the gauge or the that oil pick up came off in the oil pan. I worry most that he beat the crap out of the engine when he took it out and it is an internal engine problem. Any help would be great, thanks.