Think the "mini" in Mini-HEI is differentiating it from the larger bodied HEI distributors that are most commonly seen in the later model engines. It looks like a STOCK 235 distributor but minus the points.
The Mini-HEI for 235 engines is a small bodied HEI that is used in early S-10's (2.8's) that has been fitted with the correct length/diameter shaft, and internals to mate up with the cam and oil pump.
I've seen some data on modifying a 250 large bodied HEI, grind a little here and there, put a clamp here, adjust this till.....
I'm sure it has been done, but I know there is a whole lot more to getting it right, than luck. If you've ever had to replace a cam because the dist. drive gear was chewed up, or lost the whole shooting match because the oil pump drive shaft was out of alignment and snapped, you'll know what I mean.
Some things are best left to those who know what they're doing. If you really feel that the HEI is going to improve performance in a 235 I'd spend the money for one matched to that engine.
That's my story...and I'm sticking to it!!!
Dave