Good news, bad news. (Deja-Vu)
Good news first. Got OEM part numbers from Mazda.
Front Main Seal: B36611310B
Crankshaft Bolt: JF0111405
Bad news. Not in production. Can't get them via Mazda.
Freaking lovely. So, taking a closer look at the Rock Auto listings, several of them list diameters. I'm going to go measure the size of the hole in a little bit, after my shower. Just got home from work. I'll order a seal that seems correct, and if it works, I'll report back here and let you guys know.
As far as the bolt. I've got no idea. I'm at a loss. I might just have to make my own somehow. At least I've got that part number now. I'll be spending some time here tonight delving deep into these interwebz, trying to locate a source for them.
EDIT:
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I ordered P/N: (National) 223012
The listed outside diameter was smaller than the other National branded front main seal's listed outside diameter, so I'm pretty confident this is going to work. Now I just gotta deal with the bolt. I swear it was in the crank when it went to the machine shop. The odds of that dude finding it in that heap is about the same as the odds of me hitting the powerball, though
SECOND EDIT:
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Found the bolt! It's from the rip-off artists at Flyin-Miata, though. Freaking $18 for a bolt. Ah well. I need an MLS head gasket, too....and I at least know they sell quality ones. Before I do that, has anyone got any advice or suggestions on what head gasket to go for, and where to source it from? I definitely want to go MLS. As far as thickness, I'm fine with whatever will keep me at stock compression ratio, or slightly (very slightly) higher.
https://www.flyinmiata.com/NA/small-nose-crankshaft-bolt-1990-91.html