Rear End Swap
Rear End Swap
I have a 64 F100 with a Dana 60 4:10 ratio I have thought about swapping out to a 9 inch with 3:50's. I was wondering if they are a direct fit as far as pinion u-joint and spring pads? I could check all of this tomorrow but just sitting here at work and thought some of you may know the answer. Thanks Rusty
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Uncle Skip
- Posts: 4695
- Joined: July 15, 2006, 8:30 pm
- Location: Pearland, Texas
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banjopicker66
- Posts: 1488
- Joined: July 17, 2006, 1:59 pm
- Location: Middlesboro, KY
I know that '65 - '72 rear axle housings or tubes are a direct swap, I don't know anything about pre-'65, except that I have always believed that the axle tubes were the same for all F-100s '57 or so up to '72. Uncle Skip probably has better info on this than me. Hopefully someone will chime in on this though.
Even if you cannot get a 9" in the ratio you want right away but the axle looks good, be sure to get the entire rear axle - especially the tube/housing, chunk, brake backing plates and half-shafts. You can get the drums, shoes, springs and wheel cylinders etc at the parts houses, but those parts are the critical components. You can change out the third member easy enough later on when you get the ratio you want.
(Note: '73 and later axle tubes are wider, and require relocating the spring pads and shock mounts as well as offset wheels to avoid rubbing tires on the fenders. Axle shafts are longer too, and won't work in '72 and earlier axles.)
You get wider rear brakes, using a '68-'72 rear axle which really do help in braking power. '67 and earlier brakes are 1-3/4" wide, while '68 - '80 something are 2-1/4", a full 1/2 inch wider.
However, although the rear axle tubes are the same up to '72, the parts that bolt onto it changed after '67.
You can swap all the parts that bolt up to a '65 - '72 tube, but you have to swap them all. You cannot use '65 brake components for example, with '72 axle shafts.
For example, I put '76 F-150 2-1/4" brakes on my '66 original 9" axle housing. (The '76 donor had the common 2-1/4" rear brakes, which are the same '68 up into the '80s.)
Here are the initial changes I made:
'66 axle tube (original, I didn't remove it off the truck)
'66 3.50 3rd member for 28 spline axles
'66 28 spline axle half shafts
'76 brake backing plates, wheel cylinders, shoes, springs
'72 rear drums
Everything bolted up just fine. However, when I went to install the '72 drums, there was a serious problem - the drums touched the backing plates, and when the lug nuts were torqued down, the drums were locked tight up against the backing plates.
Turns out the '68-'72 axle shafts extend 1/4 inch further out of the axle tube than the '67 and earlier axle shafts.
When I installed a set of '70 half shafts, the brake drums fit just fine.
There was one other issue to deal with because I used '76 wheel cylinders instead of '72 and earlier:
In '73 Ford increased the bore of the rear wheel cylinders from 7/8ths to 15/16ths - and I didn't know that. That means they require more fluid to work. Because my Slick still had the original master cylinder, its bore was not large enough to push enough fluid on one stroke, so I had to double pump the brakes. Once I installed front discs and a dual master cylinder though, that problem disappeared.
One more note: Although '73 and later backing plates, shoes etc will interchange just fine with '68 and later brake components, the brake drums changed in '73. They have smaller holes for the axle studs. '68-'72 axle studs have a protruding base, so the holes in the '68-'72 drums are larger. I messed up the '76 drums I initially bought trying to get them to fit over the studs on my '70 axles before I figured out what was wrong, and eventually threw them away and got '72 rear drums.
Here is my actual setup now:
'66 original axle tube
'66 28 spline hogshead
'70 28 spline axle half-shafts
'76 rear backing plates, and all other brake parts
'72 rear drums
'76 power brakes and front discs
One more note: You will most likely have to change the driveshaft as well. The length of the snouts differ between the Dana and the Ford 9".
Summary:
Use a '72 or earlier rear axle.
Get the COMPLETE axle, not just the tube. Critical parts are the tube, hogshead or chunk, axle shafts and brake backing plates.
Plan for the dual chambered master cylinder upgrade, if you haven't done it already.
Even if you cannot get a 9" in the ratio you want right away but the axle looks good, be sure to get the entire rear axle - especially the tube/housing, chunk, brake backing plates and half-shafts. You can get the drums, shoes, springs and wheel cylinders etc at the parts houses, but those parts are the critical components. You can change out the third member easy enough later on when you get the ratio you want.
(Note: '73 and later axle tubes are wider, and require relocating the spring pads and shock mounts as well as offset wheels to avoid rubbing tires on the fenders. Axle shafts are longer too, and won't work in '72 and earlier axles.)
You get wider rear brakes, using a '68-'72 rear axle which really do help in braking power. '67 and earlier brakes are 1-3/4" wide, while '68 - '80 something are 2-1/4", a full 1/2 inch wider.
However, although the rear axle tubes are the same up to '72, the parts that bolt onto it changed after '67.
You can swap all the parts that bolt up to a '65 - '72 tube, but you have to swap them all. You cannot use '65 brake components for example, with '72 axle shafts.
For example, I put '76 F-150 2-1/4" brakes on my '66 original 9" axle housing. (The '76 donor had the common 2-1/4" rear brakes, which are the same '68 up into the '80s.)
Here are the initial changes I made:
'66 axle tube (original, I didn't remove it off the truck)
'66 3.50 3rd member for 28 spline axles
'66 28 spline axle half shafts
'76 brake backing plates, wheel cylinders, shoes, springs
'72 rear drums
Everything bolted up just fine. However, when I went to install the '72 drums, there was a serious problem - the drums touched the backing plates, and when the lug nuts were torqued down, the drums were locked tight up against the backing plates.
Turns out the '68-'72 axle shafts extend 1/4 inch further out of the axle tube than the '67 and earlier axle shafts.
When I installed a set of '70 half shafts, the brake drums fit just fine.
There was one other issue to deal with because I used '76 wheel cylinders instead of '72 and earlier:
In '73 Ford increased the bore of the rear wheel cylinders from 7/8ths to 15/16ths - and I didn't know that. That means they require more fluid to work. Because my Slick still had the original master cylinder, its bore was not large enough to push enough fluid on one stroke, so I had to double pump the brakes. Once I installed front discs and a dual master cylinder though, that problem disappeared.
One more note: Although '73 and later backing plates, shoes etc will interchange just fine with '68 and later brake components, the brake drums changed in '73. They have smaller holes for the axle studs. '68-'72 axle studs have a protruding base, so the holes in the '68-'72 drums are larger. I messed up the '76 drums I initially bought trying to get them to fit over the studs on my '70 axles before I figured out what was wrong, and eventually threw them away and got '72 rear drums.
Here is my actual setup now:
'66 original axle tube
'66 28 spline hogshead
'70 28 spline axle half-shafts
'76 rear backing plates, and all other brake parts
'72 rear drums
'76 power brakes and front discs
One more note: You will most likely have to change the driveshaft as well. The length of the snouts differ between the Dana and the Ford 9".
Summary:
Use a '72 or earlier rear axle.
Get the COMPLETE axle, not just the tube. Critical parts are the tube, hogshead or chunk, axle shafts and brake backing plates.
Plan for the dual chambered master cylinder upgrade, if you haven't done it already.
Wow! Thanks Banjo and everyone else, You gave me more good info. but I hate to tell ya I found some 3:54's for the Dand 60 for 199.00 online.
I think I may just go that route because I would really like to keep the Posi and it was the rearend that was orderer with the truck. I just want to give that 292 some breathing room on the highway. RustyW.
I think I may just go that route because I would really like to keep the Posi and it was the rearend that was orderer with the truck. I just want to give that 292 some breathing room on the highway. RustyW.
I bought another 66 truck to get a straight frame. It has a 3.70 9" in it. I also have a 3.25 9" in my driver 66 that is going to get rebuilt. One of the two, maybe both will get sold. Problem is timing. I won't start work on the truck until probably in October.
Doc is going to fuse some vertebrae in my back on Sept 15, so I will be out for probably two months realistically.
I can't take the rear end out of the truck now or it will be impossible to move around, plus my back is in bad shape.
So, if you are not in a hurry, I will make a really good deal on one of those.
Since I am installing an AOD tranny, I am thinking I want 3.70 gears, but I also have another 3.70 traction lock I am keeping for that. I am looking for a 9" rear from an 81-83 F-100 that has the car bolt pattern wheel studs. If I can find one of those, I can get rid of two of these rear ends.
Doc is going to fuse some vertebrae in my back on Sept 15, so I will be out for probably two months realistically.
I can't take the rear end out of the truck now or it will be impossible to move around, plus my back is in bad shape.
So, if you are not in a hurry, I will make a really good deal on one of those.
Since I am installing an AOD tranny, I am thinking I want 3.70 gears, but I also have another 3.70 traction lock I am keeping for that. I am looking for a 9" rear from an 81-83 F-100 that has the car bolt pattern wheel studs. If I can find one of those, I can get rid of two of these rear ends.
TxSlick66
aka MustangSteve
Money you ENJOY wasting is NOT wasted money...
aka MustangSteve
Money you ENJOY wasting is NOT wasted money...
Sorry to hear about your back, there is no rush because I'm driving it with the 4:10's anyway. I would prefer the 3:25 over the 3:70, but like I said I'm driving it and there are a hundred other things I'm doing to it right now. You had better make sure your back is fully healed before you go trying to take a rearend out. Thanks RustyW.