3.23 Open 8.75 diff needs to go

The pinions on all 3 are about the same thickness at the splines in the U-bolt flange.

Everyone beats up on the 741.

Had a 741 case with 6.30:1 open in an old 1969 USDA Forestry service 10 foot bed stepside. Top speed was about 65 MPH but it never went on the freeways. /6 with granny 4 speed. First gear and I could walk faster but it would crawl over a foot high rock at a idle.

So, I'd do the 3.91 swap but keep the 3.23's for a road trip down south of the 49th.