hello I recently bought a posi centersection with a different gear ratio for my truck at a swap meet. my truck is a 71 F100 with the ford 9". the problem is my Axles are 28 spline(I did not know this until I pulled an Axle shaft) and the centersection I bought is 31 spline. so basically im wondering what years can I use that will have the same length axle shafts and are 31 spline? or will I need to order this aftermarket? any information at all would be great! thank you!

 

You'll also have to also determine whether your axle uses big bearings or lil bearings.

Dentside axles won't work because their rear track is two inches wider.

I recall Currie Enterprises offers cut-to-fit axles.

For general information purposes...:

OutsideWidth Year Model
56.50 1969-1977 Maverick 8"
57.00 1974-1978 Mustang II 8"
57.25 1957-1959 Ford, Ranchero, Station Wagon
57.25 1965-1966 Mustang
58.00 1966-1977 Bronco
58.00 1964-1965 Falcon
58.00 1977-1981 Granada/Versailles
58.50 1977-1981 Versailles
59.25 1967-1970 Mustang, Fairlane, Comet, Cougar
60.00 1967 Cougar
60.00 1958-1960 Edsel
61.00 1964-1971 Ford Full Size
61.00 1949-1951 Mercury
61.25 1957-1972 Ford F-100 Pickup
61.25 1960-1964 Ford Full Size
61.25 1971-1973 Mustang
61.25 1967-1973 Torino, Ranchero, Fairlane
63.00 1970-1979 Ranchero & Torino
63.00 1972-1979 Ford Full Size & Intermediate
63.50 1967 Fairlane (Coil Springs)
65.25 1973-1986 Ford F-150 Pickup
65.25 1978-1986 Bronco
65.25 1973-1986 Ford Van 3/4 Ton
68.00 1972 Ford Van 3/4 Ton
69.25 1977-1986 Ford E-150 Van

 

Perhaps if you measure the length of your 28 spline axles, you could find a parts listing for 31 spline axles that are the same length? And x2 on the bearing issue.

 

Pic: Column Left - Lines 14 & 15

C8TZ-4234-A = 28 Spline Axle Shaft / Right/Left is the same / Obsolete

1968/72 F100 w/9"
----------------------
C8TZ-4234-B .. 31 Spine Axle Shaft / Right/Left is the same / Obsolete

1968/72 F100 with WDM-H - WDM-J - WDM-AH - WDM-AJ 9" rear axles & 1968/72 F100 with WEY & WFF 9" rear axles with a 9 3/8" ring gear.

Passenger Car & Bronco 9" rear axles are right and left specific.