Okay, SBF distributors come in two shaft sizes. I swapped from one to the other today. The original was .46" diameter and the new one was .51" diameter. The housings appeared identical though I didn't mic them. And, like a moron, I threw the old one out.

Now, is there any reason WHATSOEVER that a distributor with the larger shaft would NOT fit in an '86 roller-cam H.O. block where a distributor with the smaller shaft had been?

I swapped out the bronze distributor gear and turned it on a lathe to size to adapt to the bigger shaft. Now the #$!*&er appears to not fit through the block at the first ring on the housing, like it's 1/16" too wide.

I don't think it's hanging up on anything inside, as I can pivot it on the housing, and by measurement I haven't even hit the oil pump shaft, yet.

I am open to suggestions.