OK, so here is the conclusion to the story. I mic'd the shaft and it was dead on with the old distributor. I counted the teeth, and they both matched. So, I though I would try again... but it just wouldn't fit.I personally believe the gears were at the wrong angle or too thick to mesh. I took the distributor back to the parts house and told them it just would not fit. The asked if my engine was a 216 or 235? I stated it was a 228 (GMC). They said "oh! the distributor would not fit a GMC and that I should call Patrick's, because he can produce parts that fit 'odd' motors". Biting my tongue, I asked if I could get a refund. To their credit, they promptly refunded my money plus the core charge. I then drove to a different parts house and purchased another Chevy/GMC distributor that dropped in perfectly. Thankfully this saga is over.

When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
-Unknown-