Guys need some of your knowledge here. I am looking at purchasing a 1980's Dana 61 from a Ford F250 or 1980's Dana 70 from a Ford E250 with 3.07 gears to narrow and put under my 1966 F250. I have measured and both axles should narrow up fine and fit under my 1966 F250. The only problem is I would like to put a posi-traction unit in the narrowed axles but I cannot find one for the Dana 61 with 3.07 gears. I do see posi-traction units listed for the Dana 70 but I want to make sure they will work with the 3.07 gears ok. I'm trying to sort out as many details before moving forward with this swap. Any advice would be appreciated. Thanks!

 

Why go thru all this labor and expense...when it would be much easier swapping in a different ring & pinion, case and maybe the companion flange to your present Dana 60.

1966 could have either a 10 spline or 29 spline companion flange, as it depends on how many splines the ring gear has.

Dana 60: 3.54-1 introduced in 1966, 3.73-1 introduced in 1967.

F250 axle shafts are the same right/left. Econoline axle shafts are right & left specific.

 

[QUOTE=NumberDummy;14799601]Why go thru all this labor and expense...when it would be much easier swapping in a different ring & pinion, case and maybe the companion flange to your present Dana 60.

1966 could have either a 10 spline or 29 spline companion flange, as it depends on how many splines the ring gear has.

Dana 60: 3.54-1 introduced in 1966, 3.73-1 introduced in 1967.

F250 axle shafts are the same right/left. Econoline axle shafts are right & left specific.

[/QUOTE

Number dummy I swapped in 3.54 gears into my dana 60 a few years ago and it was a good improvement over the 4.10`s. The 460 engine just needs higher gears to match its power band. I do lots of highway miles between two farm sites with this truck. Thanks for the information on the e250 dana 70. I think the dana 61 will be a safer choice.