The best rear end for my application: AD

[ryans69chevy]

What would be the best or right rear end for a '49 3100? Plans are to put a 235 with a 4 speed in from a '62 chevy pickup, trying to decide between original front end or going to a Mustang II front end. Kinda swaying more for the MII since it seems to be more for what we want. We want to cruise on interstate going 70 without too many issues.

The reason we want a different rear end is because we have a 1/2 ton truck, but the rear end was swapped for a 3/4 ton rear end a long time ago. So now we are wanting to swap it out for a 1/2 ton rear end.

I've done some searching as far as rear ends from the '47-'54 era and found that if I choose one and go with a torque tube, I can only do a couple of gear ratio's i.e. 3.43, 3.73 I believe. I've also heard that going with a rear end from a 63-69 chevy 1/2 ton would be a good decision as well.

If you guys could help me out and steer me in the right direction with the pros and cons of having a rear end from a certain era that would be great. Is one better than the other? I guess if I went with a 63-69 I could have a wider selection of gears to choose from. Or if I just left the torque tube off the rear end from '47-'54 I could also get a wider selection right? Whatever rear end we choose we are going to have the whole thing gone through. We want one that won't give us troubles. Idk about the rear ends from '55-'62 if they are worth getting or not. Hopefully you guys will know the right one to get from experience. I'm also kinda worried about changing from leaf springs to coil springs if the rear end is coil like the ones from '63-'69. Is this going to present problems?

Thanks!

[Root2812]

Alot of guys ditch the torque tube because the open drive shaft is easyer to work on. If you went with a stock TT rear end the only gearing options you have are the stock 4.11:1 or an aftermarket 3.55:1 kit from Patrick's. Either a swap or a stock with the 3.55 will work fine for what you want to do. Personally I'd just swap it out.

As far as reliability of the TT... They are built pretty solid. The drive shaft is enclosed so it is protected and there is no pivot like a u-joint in the rear. The pivot to avoid the suspension binding is located at the end of the axles. Its a pretty neat design and there is a reason they have held up for 60 years.

I hope you figure it out and have fun. By the way, you have a few threads going on for this truck so where are the pictures?

[2ndGenRR]

A lot of guys go with 10-bolts from 2nd generation Camaros...lots of gear ratios available, they are the correct width and the leaf spring perches are already in the right spot. Oh, and they are cheap and plentiful...

I believe that you will have to lose the TT to run the 4-speed from the '62...

[mr48chev]

The drum brake second generation Camaro/Nova rear ends require that you run reverse offset wheels to clear the box. I can't put a standard spare on the back of my 48 with that rear end and the 255-60x15 tires on 15x8 rims just clear by a half inch. I'm not sure what the back spacing is.

The first five lug rear end I had under the 48 was out of a 61 Chev full size car. It had all the brackets cut off it and pads welded on. It fit quite well and 15x7 69 Z28 Rally wheels fit and cleared the box good. I also ran a 65 Impala 12 bolt rear end complete with control arms and springs at one time and that rear end fit quite well. When we welded up the spring buckets and brackets for the suspension to hook to we put a twist in the frame in the process or at least I believe that is how it got the twist. The truck never sat right although it drove straight as an arrow at any speed up to 120.
With the stock I beam and six lug wheels a 55/57 Chev half ton rear end fits better than anything else but again gear selections are limited. I put one of those under a freind's pickup 30 years ago that he still has.

[lazypineapple]

you want to think about your wheel tire combo too, when choosing a rearend.
on my '52 I'm using a 1974 GM 10 bolt diff.
its 60-1/4" wide drum to drum.
the Bed box of the truck is 50" wide.
the inside of the fender width is 12"

this1974 diff is about 2" too short to be ideal.
unless you use a short backspacing on your wheel.
like mr48chev said about spare tire.

subtract the box 50" from the diff width 60.25"
thats 10.25" divide by 2 , thats only 5" each side.
figure 3-1/2" BS wheel and add 1" for tire, you can see it fills up fast.

i dont know if there are gm diff in the 62" width range

since my diff came with my truck project , my fix was to have
1" hub-centric spacer/adapters made.
I can run a 8" rally with 4" back spacing wheel with a 245/60
and i have an inch of clearence on each side of my tire

[mknittle]

Originally Posted by lazypineapple

you want to think about your wheel tire combo too, when choosing a rearend.
on my '52 I'm using a 1974 GM 10 bolt diff.
its 60-1/4" wide drum to drum.
the Bed box of the truck is 50" wide.
the inside of the fender width is 12"

this1974 diff is about 2" too short to be ideal.
unless you use a short backspacing on your wheel.
like mr48chev said about spare tire.

subtract the box 50" from the diff width 60.25"
thats 10.25" divide by 2 , thats only 5" each side.
figure 3-1/2" BS wheel and add 1" for tire, you can see it fills up fast.

i dont know if there are gm diff in the 62" width range

since my diff came with my truck project , my fix was to have
1" hub-centric spacer/adapters made.
I can run a 8" rally with 4" back spacing wheel with a 245/60
and i have an inch of clearence on each side of my tire

"i dont know if there are gm diff in the 62" width range"

The 2nd gen camaros and bigger gm cars use 62"wide 10 and 12 bolts.I have one out of a 76 Monty carlo that's 62" I am planing on using the control arms and coil-overs on.


I am glad you posted your measurements. I got the same about 10 times 10 different ways and was going to measure again.

[mknittle]

OOps 62.5 1/4"0n aside

here is a width chart that may help. but I would measure anyway.


http://www.carnut.com/specs/rear.html

[lazypineapple]

My diff is a drum brake set up
Disc brake Maybe wider.
All the brackets and mounts were already cut and ground off. So I don't know if it was a leaf spring or coil spring differenal


1974
Drum to drum 60 1/4"
Flange to flange 54-3/8"
Posted via Mobile Device

[mknittle]

Originally Posted by lazypineapple

My diff is a drum brake set up
Disc brake Maybe wider.
All the brackets and mounts were already cut and ground off. So I don't know if it was a leaf spring or coil spring differenal


1974
Drum to drum 60 1/4"
Flange to flange 54-3/8"
Posted via Mobile Device

I just measured one from a 69 nova it measures the same as yours.

[ryans69chevy]

So is it possible to use the stock rear end from a 49 chevy 1/2 ton and take the torque tube off, which would allow for a wider range of gears? Or is it even possible to take the torque tube off on these things?

[Root2812]

No you can't keep the stock 49 rear end and remove the TT. Its all one unit. Plus its the rear end that doesn't have any other gearing options so even if you could ditch the TT for a drive shaft you would still have the same issue.

[ryans69chevy]

I think I've decided on getting a rear end from a 63-69 chevy pickup. I was thinking about the 2nd gen camaros, but I don't want to worry about tire fitment issues and wondering if it will clear the box or not. I think with the rear ends from the 63-69 chevy pickups this will give me a wider range of gear ratios and fitment should work out good since I've heard of a lot of ppl switching to these years...

[ryans69chevy]

I found on a link that says the 64-69 chevy pickups are suppose to have 60"-61" rear ends. I measured on my '69 and it gave me 56 1/2". This was measuring from backing plate to backing plate. How did they come up with that measurement? Or where is the correct spot to measure from? The reason I am asking this is because I'm going to go look at a rear end that the person claims to have taken out of a 64-69 chevy pickup, but I want to measure and make sure that that rear end measures the same as my rear end in my '69 which I know is original. I am going to put this under the '49 3100.

[jackson]

ive got some rallye wheels 8in with 4.5 backspacing. so what rearend should i look for

[DransportGarage]

Originally Posted by ryans69chevy

I found on a link that says the 64-69 chevy pickups are suppose to have 60"-61" rear ends. I measured on my '69 and it gave me 56 1/2". This was measuring from backing plate to backing plate. How did they come up with that measurement? Or where is the correct spot to measure from? The reason I am asking this is because I'm going to go look at a rear end that the person claims to have taken out of a 64-69 chevy pickup, but I want to measure and make sure that that rear end measures the same as my rear end in my '69 which I know is original. I am going to put this under the '49 3100.

The 60"-61" on my '69 Nove rear end is from axle flange to axle flange (i.e., between the faces where the wheels bolt on). To me, that's the dimension that counts.

[mknittle]

Originally Posted by DransportGarage

The 60"-61" on my '69 Nove rear end is from axle flange to axle flange (i.e., between the faces where the wheels bolt on). To me, that's the dimension that counts.

Yeah, the backing plate to backing plate doesn't tell you anything because there are several backing plate/drum combos. I have a 10 bolt from a Pontiac station wagon that has huge drums and backing plates offset of an 1 1/2" from the outside of the flange.

[solidaxel]

Originally Posted by dransportgarage

the 60"-61" on my '69 nove rear end is from axle flange to axle flange (i.e., between the faces where the wheels bolt on). To me, that's the dimension that counts.

............... X 2 ............

[DransportGarage]

...and that was a NOVA rear end, not a Nove. I shouldn't be allowed to turn my PC on before 6:00 AM!

[_Ogre]

chevytrucks.org scroll way down.

[c6_rob]

Originally Posted by _Ogre

chevytrucks.org scroll way down.

Thats a great link

[ryans69chevy]

Can anyone get me a pic of where to start the measurement? "Between the faces where the wheels bolt on?" I'm not really too sure where that is...

Thanks for the link as well!

Thanks,
Ryan

[mknittle]

Originally Posted by ryans69chevy

Can anyone get me a pic of where to start the measurement? "Between the faces where the wheels bolt on?" I'm not really too sure where that is...

Thanks for the link as well!

Thanks,
Ryan

yeap, that's it. where the wheels bolt on.