...and it did help a lot! Thanks! The PO said that they were a complete drop-in.

Wild Horses shipped the kit reasonably fast- about a week to AK. They charged me $45 for FedEx. I think the motors could have fit in a Priority Flat Rate box for $15, but they didn't think so. Whatever.

The extra nuts I added to my order on the phone for $15 must fit a Bronco, because they're completely the wrong diameter and thread pitch for the wipers I got. An email on the subject was ignored. With shipping and going to the PO, it's not really worth my time to press it over $6 nuts, but now you know.

The 1.5" spacers from Lowes worked perfectly. I had to run a drill through the big ones to get them over the brass threads. A little sandpaper work would probably do the trick too, just smoothing out some roughness inside.

I noticed two things while Googling these motors:
-boat folks like them too, but pay a lot more. Wild Horses was the cheapest I could find.
-they come in different offsets (length of threaded shaft). Shorter ones might not require the spacers. I'll know more about that when I see the truck.