I got a cheap HEI distributor for my 1976 F150 about a year ago. After that, I blew a head gasket and bought a 390 core and had it completely rebuilt. I took months and months to get the motor rebuilt and get the truck back on the road. When I went to put in the Chinese distributor, the shaft would not rotate, it was stuck. My mechanic got it working again and in the process he replaced the roll pin that secures the gear to the shaft. At that point it seemed that all was well until about 1000 miles on the new motor the gear came off the distributor. The roll pin had broken. I replaced the roll pin and everything seemed fine again, but after another 600 miles the same thing happened. I have wondered if there is an issue with my oil pump that is causing the stress on the distributor gear. I can turn the oil pump by hand using the distributor shaft, but it is tight and takes a fair amount of force to turn. Anybody know if that’s normal or concerning? I went ahead and ordered the $400 Davis Unified Ignition distributor. I was not inclined to believe that it’s worth the extra $300, but under the circumstances I’m going to try that before hoisting the motor to replace the oil pump. Anybody ever have this problem?

 

Anything is possible but I'd suspect a crap chinese distributor before an oil pump.

I have seen tons of problems with the junk imported HEI distributors and I've had my own problems so I'm weaned off them. some say the DUI brand are better some say they're junk with better electronics. I never could find where it's claimed they're US made. or where they're not. some say they're imported crap assembled in the USA. I don't know, I'd like to know.

I'll just stick to the old durashart system. it's not perfect but it works. your '76 would have come with durashart so if you wanted to go back the wiring should be there . that's what I'd do.

 

All the original ignition wiring was either melted or so brittle you couldn’t strip the insulation without the strands of wire breaking off. Instead of running new wires, I deleted them and installed the HEI. Going back to Duraspark would be an option, just not really an appealing one. I’m not super concerned with which system is better unless it turns out that even the top of the line HEI gives me trouble. If that does happen I may grudgingly go back to a duraspark. Or I might get really fed up and buy a brand new truck. Everyone thinks I’m crazy for driving a truck that breaks down all the time. I’ve replaced or had rebuilt everything except the rear end at this point. And now I’m on my second brand new starter and now a $400 distributor. It just goes on and on.

 

That's why I own two of these old things. Always got a back up just in case. lol. Most people would probably just say get one nice, new truck, but I love these old things.

 

It may have had a high volume oil pump installed because more is always better right? More volume equals more stress. I believe some folks will drill another hole perpendicular (just below the first) and install a second pin to help distribute the load.

 

If the shaft is any good it won't drill very good. but, the chinese one you can probably drive a nail through it.

I've run a lot of HV pumps and never had an issue.