[Clarke]

My ‘62 has the 5/16” line with the straight arm pump, which I have replaced seven times within the last two years. I have driven my truck several thousand miles the last couple of years and after several hundred miles the pump starts spewing oil out of the weep hole near the body flange that is screwed together.

I’m assuming this is mostly due to the rubber diaphragm being too small diameter and constantly running the engine at 3,400 rpm to maintain 65 mph.

A couple years ago I almost swapped the pump to a later model, which has a larger diameter diaphragm with angled arm, but I wasn’t sure if it would work and for that reason was hesitant to change my fuel lines from 5/16” to 3/8” dia. I’m assuming with the bent arm the stroke travel would be less, but with the larger diameter diaphragm (increased surface area) maybe there would still be ample fuel volume and the pump would last longer? I ended up taking the later model pump back to Napa and still changing out the original. I will most likely upgrade to electric fuel pump.