OK, finally figuring this out. Was feeling pretty dumb 20 minutes ago.
1985 FJ60 with BTB Springs, H55F, and Onan Turbo Diesel
Onan L634T (aka Cummins 6A3.4T). This is a 3.4, IDI turbo diesel found in really old UPS trucks. Nice little motor, harder to find parts for these days.
The FJ46...