found this and it explains it.

http://static.speedwaymotors.com/ima...f/91067433.pdf

 

Explains somewhat, but has mis-information. First, they are using non stock parts, those are not OEM starters, and may or may not have any relation to stock parts. Second, their statement about the number of bolts per application is BS. FE engines used a 3 bolt starter, whether manual or auto. SBF Windsors, Clevelands(335 series) and 385 series big blocks used a 2 bolt starter.

It still doesn't address the spacer issue, which if you were to put that spacer in between the bellhousing and starter, you'd lose the piloting of the flange on the starter nose in the hole, and would be relying solely on the 2 bolts to keep the starter in alignment with the flywheel. Your mileage on how well that works may vary.

 

Correct - I believe they have a single starter nose and this shim is meant to adjust for differences that would otherwise be accommodated by the stock Ford nose correct for application.

I can tell you that you don't want to do this. Many years ago, I was in a hurry with a deadline (going into military) and failed to install my engine block plate. This meant that only the starter bolts were locating the starter in relation to the flywheel.

I got very good at changing starters as I'd eat the bendix gear up quickly. The lifetime warranty at the big box stores doesn't cover this, by the way.

I tried cheating and split an engine plate at the alignment dowels and shimmied them in from top and bottom as two halves. That helped, but didn't solve the problem. Eventually, I was forced to pull the trans and flywheel because the flywheel teeth were damaged beyond use - I flipped the ring gear on the flywheel and installed the proper engine plate and never had another issue - that engine/trans combo is still going strong in another vehicle.

The moral of the story, you need that indexing provided by the engine block plate. The starter bolt holes are slightly oversized to allow the block plate to put the starter exactly where it needs to be. The bolts just hold it in place, not locate or index it.