I know one problem with the so called mini Hei's if used in a 235/261 or GMC inline.The Hei has a flange on the distributer similar to the 230-292 6's or the small block V-8. When the Hei with this flange is bolted down,the shaft may force down the oil pump drive resulting in chewing up the pump or at worst a pump siezure.Since the original distributer is clamped in place by a semi floating affair,the accuracy of the surface machining of the distributer pad wasn't critical.
I suggest anyone planning to install a mini Hei in an old block,carefully check the to make sure the dist. isn't slammed down on the oil pump and the driven gear meshes properly with the cam drive gear.This is info the guy who makes these units doesn't seem to hand out, when modify an engine with non stock components, check all clearances
On the later 230-292 engines,the above isn't a problem
