I have located a good 9" rear end from a '71 F-100 to swap into my '54 F-100. My F-100 currently runs a stock driveline, including the original manual 4 speed, driveshaft and a Dana Spicer diff. I have read the Forum article on rear-end swaps, and I am trying to keep this as bolt in as possible, as I don't have access to a complete shop and welding. I bought the axle outright off the vehicle, so I don't have the '71 F-100 to use as a referrence point.

It appears the spring pads will line up fine without any welding. I have the '71 u-bolts and anchor plates for the larger diameter (3") axle tubes on the new 9" diff.

I am concerned about the use of the existing driveshaft with the new diff. Are the U-joints used on the '54 and '71 F-100s the same? Is this too bolt in only? And is the 3rd member about the same size, such that the driveshaft doesn't have to be shortened or lenghtened?

How about the emergency brake cable setup? Does the sheathed cable running from each drum to the cable from the e-brake require modification?

Any information or tips from somebody that has done such a swap would be appreciated. Thanks and regards, Jeff

 

I was going to do a swap and either buy a used rear as you did or a new customr made Mosier.

After doing all the research, I bought new gears for the Dana 44 and coverted it to a posi, repalced all the bearings etc. Unless you are going to be running over 450 hp and beating on it the Dana 44's hold up very well. I have less that $800 in total cost on my rebuild. Many suppliers who sell the gears and other parts.

I am running a ford Racing 306 with 340 hp and 350 tq and "use" my Dana 44 and it runs great (burnout here and there along with a lot of 1st to 2nd gear chirp)

Bryan

 

Thanks Bryan
Yeah, thought about that too. I have 3.92 gears in the Dana, and I think I would have to replace the whole carrier + axles to reduce the ratio.

I have a balanced and blueprinted Y Block, but it is not producing anywhere near the output you are handling. I am sure the Dana will take output handily.

I have found a good 3.25:1 9" and it is only $150 bucks, so if it is a bolt-in, it is both cheap and effective

Did you get a whole different diff, or did you replace the axles and center section?

Jeff

 

I am planning on "bolting in" a 9 inch out of a '69 f100. I had to track down the lower shock plates from a '57-'60 f100...what shock setup are you planning?

 

I have the shock plates off the "71 F-100. The Forum article says you need them as the 9" axle tubes are 3" in diameter vs. 2 1/2" on the Dana. I didn't see them on the original truck as they had already been pulled - will these work on the swap, or are the shock mounts in different place??

 

I kept the axles, replaced carrier, gears and bearings etc. Just gears and carrier you can get away with less $$. I figured by the time i bought a used 9 inch, rebuilt it with new parts, hooked up the ebrake, misc welding, new spring U Bolts etc. Keepng the Dana 44 that I had was easier and less expensive. Originally I was going 9 inch also as it seemed thats what everyone else did because you could not get parts. I found out that the parts are out there and to me it was then a no brainer. There are lots of reasons to go either way, nothing is right or wrong.

 

I can't say how much of what's involved with an earlier truck applies to your '54, but here is what I had to do.

The 9" had brackets welded to the tubes for the shocks, but they were in the wrong place and angled differently. I cut them off and re-welded them, measured the required shock length. It turned out my old front shocks were just right. You may be able to locate them so stock rear shocks work.

My springs are 2" wide vs. (I think) 2.25" for the later axle. I bought new U-bolts and used some Brand X spring plates from the boneyard, no problems. You should not re-use 40 yr old U-bolts.

The e-brake cables plugged right in and work with the new axle.

The hydraulic brakes hooked up but I had to use the original junction block on the new 9". The later trucks used a hose to the frame that is integral to the block (non-replaceable). No big deal, the old block bolted right up, with a little tweaking on the hard lines.

Depending which yoke is on the 9" (there is a Long and Short yoke), you may have to lengthen the DS an inch. Which means, new DS tube ($200 +/-). I switched to the Long yoke and no changes were needed, but the yoke costs about $75 and changing requires a new crush sleeve and setting pre-load on the pinion bearings to do it right. At that point you should replace the seal at the same time.

Depending what yoke you have, the rear U-joint may need to be a hybrid, i.e., match the 9" on 2 cups and the DS on the other two. No problem, Spicer makes them that way or a shop can figure it out. Just measure and shop accordingly. If you have a new DS made, it can be accomodated at that time (more $$).

I think that's about it. It isn't a Bolt-in, but it's not too bad.

Edit -- one other thing, the lower shock bolt used with later 9"s is smaller diameter than the studs on the stock setup. Easily cured with a steel sleeve for the lower bushing that comes with shocks, just need to hunt some down.

 

In the research I did, I found Ford used the same part number u-joint for a ton of years - officially listed 57-77 I believe, my '48 had the same part number when I looked it up in the paper books.

Macs Antique Auto lists the part # 4635-UJ680 as being 48-78 which jives with what I found. (I even found 80's SAE vehicles used the same - it was the switch to metric that finally killed the use of it)
The exceptions listed in the part book was "except 460 engine" - which I think is kinda a lie, it should read except 3700# axle (9 3/8").

Common mechanic's calls the Ford u-joint a 1310 (and most mechanics simply call it a "Ford u-joint")
best bet, look up both years (the 54 and the 71) in a parts book and check - bet they both list the 1310.... but you got to know do you have heavy duty axle / hi performance, etc.
Anytime you tear apart a u-joint that has significant mileage you should probably replace it, they aren't terribly expensive (I didn't and it blew out 600 miles later).
Got a new one, drove on it 100 miles, then took it out as part of a t-5 install (you need a crossover u-joint, from Ford typical to modern metric Chevy for what I did).
Brake lines came out in exactly the same place, spring perches are exactly the same place, shocks as Ross mentioned are probably a slight change. As long as you are mixing and matching standard (non-hipo) with standard (non-hipo) then all the yoke length and u-joint stuff should be bolt in, when you start trying to put in the hi performance rear ends then you need to step back and look at things.

I would advise you to spend the $5 for a new front seal proactively, instead of filling it, finding out it leaks, and then tearing it all apart again (#learnfrommyfail)

Be safe

 

Wow guys, all great stuff! I am getting more inspired...

I was looking at Midfifys catalog and see they have a 3" conversion kit that includes new U bolts, spring base plates and new weld on lower shock mounts for "any 3" axle with the diff mounted below the spring". That sounds like me! I can drive it to a local welder w/o the shocks to have them weld on the new mounts, and use the stock upper mounts.

Anybody have experience with the Midfifties kit, or can suggest some other good aftermarket kit to make this easier??

Both the stock diff and this junkyard Ford 9" are not HiPo, so I am hoping for good karma on the universal joint. Anyone have an opinion on how much spline in the rear of the tranny is adequate?

Thanks all - keep the clues coming!
Jeff

 

I measured the stock setup at about 1.25" out from bottomed on the trans shaft, with the truck on the ground, but it's a different setup than a '54.