A common mistake people make when installing distributors is to fail to get the housing deep enough into the block to engage the oil pump drive slot. There's about 1/4" of engagement between the tang on the end of the distributor shaft and the slot in the pump drive shaft. The engine will start and run with the dizzy that far up- - -it just won't have any oil pressure. "Knocking" is sort of like the chest pain a heart attack victim experiences- - - - -it's an absolute necessity to find out why it's happening, while there might be a possibility of corrective surgery instead of a funeral. Do whatever it takes to be absolutely sure you've found and fixed the problem. I'd expect to see a minimum of 30 PSI on a cold engine while spinning the pump with a 1/2" drill motor. If it's showing pressure with the drill, then figure out why it's not starting, and do a short test run to see if it still knocks. If so, tear it down and start over.
Jerry
