When you say "mini HEI", are you talking about Langdon's distributors?
Have you already purchased it, that you know the shaft is smaller?
I pulled a internal-coil HEI out of a 250 that had a lower end diameter of .4666". The shoulder was just up inside the bottom of the gear and below the roll pin and I did not notice it. The bearing was nice and tight so I just dropped it into my engine(292). It wobbled around like crazy. The oil pump tang was sliding back and forth on the pump slot every half revolution.
That one was in a Olds or Buick with a 250.
Don't use it.
problem with the large hei as the lower part of the shaft has a wobble joint.
I have only seen one of those. I pulled it out of a '75 Nova and it had the external coil. I'm not sure that it is factory. I think it's an after-market rebuild and that is how they repaired a damaged shaft. I don't like the looks of it, so I'll probably never use that shaft.
I used the housing and another shaft and created the problem Tony mentioned. I placed a couple shims between the gear and the bottom of the housing to take up what I thought was excesive play. I left about .004". Unfortunately, with the shaft tang in the pump, the housing was about .010" plus the gasket above the block with the clamp tightened. Not good.
