fuel pump spacer 72 chevy 350 c10

[crosby]

should there be a spacer between the fuel pump and the block on a 72 Chevy C10 stepside 350? I have run the casting numbers on the block and it appears to be the correct (original?) engine. This is my friend's truck and for some reason the fuel pumps last about 3 minutes and self destruct. I am wondering if the pushrod from the cam that drives the fuel pump is bent or something like that. I suggested he get a new pushrod and fuel pump. Any other ideas? Thanks very much guys!