Hello all, I have a 1989 Ford F250HD, 351W, E4OD transmission, sterling 10.25 rear axle, 2wd. My question is, just out of curiosity, what upgrades would have to be done to make it effectively an "F350?" I know adding leaf springs is one of the things, what else? Is there anything that can't be changed? Do both trucks use the same frame or is the F350 frame beefier? I know when it comes right down to it the number on the VIN is what matters as far as what it is rated for, I am just curious what would have to be done to make an F250 an F350 mechanically. Thanks!

 

Unless my memory is failing me, both f250 and f350 2wd use the same front axle. Since your f250 is HD, it will have the full float Sterling 10.25" rear axle and 1/4" frame. Same as the f350. It really does come down to springs in the 2wd models. 4x4 has a completely different front axle between the two.

Anyone that knows better, correct me if I'm wrong. I'm pretty sure of that info though.

 

F-250 and F-350s use the same frames, engines and transmissions, so no changes there.

I don't know about the 2WDs, but for a 4WD the only difference in the rear end is that the 4WDs have a taller block between the axle and spring (to compensate for the higher ride height of the solid axle in front). But they use the same springs and rear axle. I don't know but I'd guess there are no differences between F-250 and F-350 2WDs in the rear.

As GoinBoarding said, the 4WDs use different axles (solid Dana 60 for the F-350, TTB Dana 44HD or TTB Dana 50 in front) along with different front springs (stiffer on the F-250 due to the different geometry of the TTB suspension). But I don't know what differences there are in the 2WD front ends.

 

The ONLY difference between a 2wd F250 and a 2wd F350 is.....
The emblem on the fender and the GVW in the door jam

Same..
Springs
frame
axle
sway bar
shocks
tires
gear ratios
etc