85 B250 (light duty 5 lug) parts donor in the driveway is 8 3/8 rear end with I assume 11" drums, (they are visually much larger than the known 10x2" drums on my 79 B200 with 8 3/8 axle. )

Keeping that axle for my 79 since its also got 2.9x gears for highway driving.

Worked on an 87 D150 last year and it was the same way. Didnt measure them but those drums filled up the inside of the wheels.