I am looking to change my rear end gearing to 3.54 r/p. I have found a set and seller states it's a 6 spline. I believe 34 was 10 spline. Any ideas on this. Before I spend big $$$s need advise. Posted using the Full Custom H.A.M.B. App!
Need to have the OD of the pinion bearing surface decreased so you can use the 18- pinion race and two bearings. Then the OD of the pinion needs to be decreased so it will fit into the 34 banjo. The banjo will also need to be relieved ONLY if the ring hits any of the housing. Yes the 34 has a 10 spline but 35-40 use the 6 spline and the solid drive shaft of the 38-40 uses a coupler, it can be cut down in length and welded to the 34 drive shaft, the final length of the 34 drive shaft is about 3/8" shorter, but after temp install before final welding the shaft the final length can be tweaked. If your using the original engine the 3:54 is a bit too high especially if you have any hills to climb, you may want to consider the 3:78.
It can be done if you have access to a lathe and you are ok with fabrication. I don't have the article, but there was an old "Ford Times" article which showed how to take a later model R&P and turn down the diameter of the pinion to make it work. Can anyone on here post a copy? We did this for my dads 33 pickup, but I used a 39 Merc R&P, cut off the Drive shaft and had splines cut onto it, so it was slightly different. If I recall correctly, we had to turn down the pinion gear diameter as well as the forward pinion bearing surface on the shaft. We were able to leave the ring gear alone.
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