what are the year breaks for perch width, spline count, shaft size, knuckle style, etc. i'm asking b/c i read an article saying that the 78-79 f350 60's had 1.5" shafts and i always thought that 60's had 1.31". it just sparked some interest. i would like to have an idea in my head about what years had what. i would especially like to know about the different perch width years. thanks- russel

I am by no means an expert, but.

REAR 60's had 1.31" shafts, 30 spline. I don;t think any ford FRONT 60's had 1.31" Inner shafts??

As for perch width - I *believe* the move from approx 32" to approx 36-37" (?) was sometime in the mid 90's ??

I'm not helping much, am I??

D-60 fronts on Fords:

'74-'75; 30 spline inners and 19 spline outers, closed knuckle, drum brakes, low pinion.
'76-'77; 30 spline inners and 19 spline outers,open knuckle, disc brakes, low pinion.
'78-'79; 35 spline inners and 30 spline outers, open knuckle, disc brakes, high pinion.


eric

And impretty sure they changed from kingpin to balljoint in 1985 or 86

Wow, lots 'o off info here.

Most '78/9 front 60s (high pinion disc brake) had inner shafts that were 1.5" at the splines but necked down to 1.31 for the body of the shaft. Spring perch width was about 32"

'80-'85ish there were no front 60s, Ford was still high on crack and proud of their D50 TTB.

The live D60 returned in '85 or '86 (ya never know w/Mother Ford) w/36" spring pad spacing and the diff offset several inches more to the driver's side. The inner shafts no longer necked down to 1.31". King pins remained until the early/mid '90s - there was just a thread on this in General 4x4, do a search.

Here's what I'd like to know: will an '85-92ish king pin knuckle work on a '79 front? If no, why?

The inner shafts no longer necked down to 1.31".

So are people just replacing the 70's inners with later model inners to lose the reduced diameter? Lengths the same?

Here's what I'd like to know: will an '85-92ish king pin knuckle work on a '79 front? If no, why?

I don't see why not, as it is common to swap Chevy parts from the kinpin out.

Originally posted by BillaVista
[B]

So are people just replacing the 70's inners with later model inners to lose the reduced diameter? Lengths the same?


Well, now that I think about it the lengths wouldn't be the same because the newer diffs were offset more. I'll track down Ultim8kaos, he did this on his front 60 (eliminated the necked down shafts).

My front 60 was from a '79 F-250. It had the necked down inner shafts. I wanted spares so I purchased new Spicer units and the new replacements were of the newer style and were not necked down.
The lengths are not the same as the diff offset is about 3.5" different from the earlier 60's to the later ones.

Possibly just a running production change on Spicers part?

Yep, and the only other thing to mention is that the 78/79 brakes are much less likely to fit 15" wheels than 85-97 brakes. The later ones do it pretty easily with 2.5" BS

15" wheels fit fine with the 78/79 brakes with the 2.5" backspacing on the wheels. MINIMAL grinding necessary! :flipoff2: :D ask me how I know.