Narrowing a HP Dana 44 for a Jeep YJ
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This project will show you the main steps in narrowing a Ford F250 High Pinion Dana 44 to fit into a Jeep Wrangler YJ. This project was for a YJ that was keeping the suspension in stock spring under axle fashion - but the steps are almost all the same for a spring over axle conversion. The goal of this job is to narrow the axle to 1980's Jeep Grand Wagioneer width which is +/- 60".
The first step is finding the right axle - the ideal axle is a 1977-1979 HP F250 or 1977-1979 Super Cab F150. Both axles are high pinion Dana 44's with leaf spring perches. The F250 has 8 lug hubs and the Super Cab has 5 lug hubs. Either can be converted to whatever lug pattern you want, so either axle is a great start. The key to these axles is the fact that that have real axles tubes and no radius arm mounts to deal with - and if you are going to spring over axle, the drivers side spring perch is already cast into the differential.

High Pinion F250 axle - stripped down and ready to be narrowed.
Close up of cast in drivers side spring perch.
First step is to cut/grind/torch off all the old mounts and tabs.Grind them all smooth when you are done.
The next step is to grind off the inner steering yokes as you would for a cut and turn or any narrowing job. Since we will be narrowing the axle more the length of the steering yoke - you can get pretty aggressive in grinding into the axle tube. That section of tube will be cut off, so you are not going to be weakening anything.
Once the yokes have been removed you need to mark you 'cut' line and get ready to narrow the axle. You can use a hose clamp or piece of tight fitting tube to go around the axle tube to get your straight line all the way around. To calculate where to cut you need to know the original axle shaft length and the axle shaft length you plan to use. The chart below shows you the length in inches of the axle shafts we are working with. Make sure you measure 3x and cut once!
To cut the axle tube you can use just about anything that will cut metal. I use either a porta-band or a metal chop saw. You can also use a sawzall or an angle grinder with a cut off wheel. Once the tube is cut you want to clean up the cut edge and prepare the tube for sliding the yokes back on. I use a flap disc on my angle grinder to smooth everything out without removing too much material.
Cut and cleaned up axle tube - ready to reinstall the steering yoke.
Line marked at the spot the tube needs to be cut . If you look close you can see the center punch mark that is the exact point.
Yoke reinstalled and welded on to the axle tubes.
With both sides cut and cleaned up - you can reinstall the steering yokes. If you haven't already looked at the Cut and Turn link above - please take a look now so you can see the steps that I am skipping.
For this spring under axle project the next step is adding spring perches.
When you go to add back spring perches you need to measure out your spring perch centerline distance and make sure it is centered on the axle. For this YJ swap the spring centerline distance is 31". The passenger side perch was set first, with the caster and pinion angle already set the perch was set so that when installed in the vehicle the caster angle would be correct (for this job caster was set to 6.5 degrees). In the picture above you can see how the spring perch is clamped onto the axle tube to get the angle perfect before welding.
Driverside SUA perch fit into the cast section of the axle.
For the driverside spring perch I needed to grind out a bit of the center section webbing and create a flat spot for the perch to sit. It is just a case of grind, test, repeat. With a 31" spring perch spacing and unequal axle cuts on each side the new perch does not exactly line up with the old perch, so even if you were going SOA you'd still need to add a new perch, or at least a new centerpin hole.
Completed HP Dana 44 with Grand Wagoneer width axle shafts. Setup for a SUA Jeep YJ.
With both spring perches welded on - the fab work is complete. A little paint and you are good to go!!