On a loosely related matter... I’ve got drum brakes, cylinders, & backing plates from a ‘77 FF Fj45 front axle if anyone needs parts. I’ve gone disc and will never use them. They’re massive and oversized compared to 40 components.
When I converted my FF rear axle +/- 20 years ago, options were limited. I used Blazer callipers and rotors (about 1.25” thick vented rotors). The original design used a 1/4” thick stamped steel plate that bolts to the Chevy knuckles. My original plan was to adapt them to the Toyota axle... Island Rod service instead started from scratch and welded custom mounts to the axle. The owner said it would be easier than adapting them to work... I’m not sure it was since it took a full day to do the work (to the tune of $800). For a while I was choked about the cost, but every time I look at the work I don’t regret paying for the artistry.
I used newer front Landcruiser studs to mount the rotors to the rear of the 45 hubs. Now stock Chevy rotors, callipers, and pads can be replaced for dirt cheap without any modifications. They were used in 6 bolt 4x4 Chevy Blazers, Suburban, and 3/4 ton trucks from ‘75 till the late ‘80s... possibly even the 90s. New callipers are $17/each and rotors are about $60 each. It’s almost not worth the effort to clean them up when I replace the pads... they’re so cheap and easy to get hold of.
