9" rear in a jailbar truck

[TomT/Williamsburg]

A 9 or 8” is alot easier to work on, parts are still readily available, and it’s a much stronger than a banjo, 8 or 9”, for a 1/2 ton truck. For me, I think 75 mph at 2500 rpm - there are calculators out there to figure this out w/5th gear ratio, tire diameter, gearset - a flathead’ needs hesat and its sweetspot is 22-2800 rpm. My avatar w/stock flathead can run 85 mph at 2800 rpm and never missed a beat and never overheated. Stick in the 8 or 9” - you won’t regret it!