I got the gears from a member

RussellSullivan said
89 Fifth Avenue AND 1980 Diplomat. Don't worry, I switched to 3.21

Previous 0-60 was measured with a sundial

I stuck one of those diffs in my 51 pickup, not realizing the gear ratio. It would go 30 mph at idle in first gear with the 265/75 16’s on it. Doubt that 80 hp flat head would pull in 3rd gear.