Dana 60 to 8 lug 9” swap 72 F250

[ChrisB]

I recall hearing about an 8 lug axled 9 inch for heavy duty F100 or F150?

If the 9s described come from a bump side I’m thinking the swap might be simple but seem to remember spring perches being different width.

Fill in the blanks fit me.

Are the 8 lug 9s 28 or 31 spline? I’m doing this step
To get ratio flexibility for some testing. I’ll end up using 2.47-3.25 ratios.

My 60 has 3.54 ratio as high as you can go as far as I know. Not sure if new D60 3.31 ratio and maybe others can be used in old Dana 60 rears. Thanks

[basketcase0302]

="ChrisB"I recall hearing about an 8 lug axled 9 inch for heavy duty F100 or F150?

If the 9s described come from a bump side I’m thinking the swap might be simple but seem to remember spring perches being different width.

Fill in the blanks fit me.

Are the 8 lug 9s 28 or 31 spline? I’m doing this step
To get ratio flexibility for some testing. I’ll end up using 2.47-3.25 ratios.

My 60 has 3.54 ratio as high as you can go as far as I know. Not sure if new D60 3.31 ratio and maybe others can be used in old Dana 60 rears. Thanks

In over 40+ years of working on our trucks I've never heard of such an axle, (or seen it in parts books or in the technical drawings here). You realize that high of an axle ratio would leave your trucks towing ability pretty much useless don't you?:
https://fordification.com/tech/schematics.htm

[ChrisB]

Hmmm , how bout a semi float 8 lug D60? This is a memory from about ten years ago.

The truck has a 6bd1t np435 and an Eaton od with about a .75 ratio. I’ve never been able to identify the od gearbox even with casting numbers... kinda odd.

It turns about 1950 rpm at 65 mph in od with 235-85-16.
I already own 3.70, 4.56 9” third members installed in other stuff.

Looking to slow it down. A 2.75 would put 4th no od about same place as 4th od now. But not for towing specifically. I’d prefer it to be a full float 9 though mainly looking to check fuel mileage and just see how it is noise wise etc at lower rpm. Truck is capable of 26-28 mpg as is at 65 with boost 0-2 psi, relatively low load. Usually gets 22-24 mpg mixed stuff I used to do. Truck sits in storage for most part now because I don’t have room to keep everything at round at same time ... yet.

[basketcase0302]

[hfdco4]

Actually it was the other way around. Back in the day there was a Dana 61 with the 5 bolt pattern.