Starter Bolt size - HELP!

I replaced my AX15 bellhousing (it cracked) with one out of an 04 wrangler, and the threads in the bellhousing for the starter are all messed up, so I need to re-tap the threads so I can get the starter back in. What should I tap it to?

I have read tons of different threads about which bolt is what and every single one of them contradicts the other. It seems there are 2 sizes that people have agreed on: M10x1.5"-28mm and 3/8-16x1.75. but which hole is which? Is the lower bolt hole supposed to be M10 or 3/8?

One bolt goes into the starter itself, so check that one since it won't be wallowed out, I think it's the M10 one but not sure. The other is the 3/8 one. I think the 3/8 goes into the bellhousing but may be wrong.

I believe the one into the starter housing is ISO, and the one into the bellhousing is SAE (don't know why. Doesn't make sense. The transmission is Toyota, the starter is Mitsubishi.)

Use of a Heli-Coil is prudent, and you can use that to make both screws match, if you like.

However, the starters I've removed from the AW4, AX-15, and BA-10 have all had one ISO screw (M10-1.75) and one SAE (3/8"-16.) No, I have no idea why...

I'm pretty sure the one into the bellhousing being SAE is because everything else on the engine/bellhousing interface is SAE, so they stuck with it for that bolt.

But the starter they specced was already designed with the M10 thread in it, so they just went with metric for that bolt.

Sounds like 5-90 and I both are pretty sure of the same bolt setup... verify before making metal shavings, but bet on it being accurate.

You guys are correct. The starter was the M10x1.5 (NOT M10-1.75), and the bell housing was the 3/8-16x1.75.

Thanks guys.