The Stovebolt Site Forums The Shop Area Engine Shop What rear axle did you use on your 47-53 Chevy?

Im considering doing an axle swap on the 1950 3100 I just picked up. It still has the original torque tube setup. I searched last night but didnt find much. So what axle did you guys use? I want to find one that has same bolt pattern as stock, and takes as little modification to mount to the springs as possible. I have a few in mind that I want to take measurements on at work but Id like to hear what you guys have done. Thanks!

-Nick

well, dunno how much you want to spend or what you have in mind, im bagging my 47 and building it from the ground up and am stll using my stock rear housing, swapping out pumpkins, if you want higher highway speeds decide what trans you want and go with a diff rear end, im still using my 235 with a saginaw 4 spd and the rear pumpkin swap is a 3.90 rear gear, so im lookin at 60 tops highway, but im all about going low and slow, hahaha, any more questions feel free to ask!

Not looking to spend a whole lot, I mainly just want an axle that is as bolt on as possible that still uses the stock bolt pattern. I want to use a T5 transmission from an 85 Camaro so I need an open driveshaft. 60 mph is a good top speed for this truck, however I want to be able to drive it on the highway so it must do at least 55-60 though.

Edit: Ive read about a few people using Nova rear ends, how 'bolt on' are these axles? I also saw somebody with a '72 Nova rear axle that was 6 lug, how would I be able to do that?

If you are going with a T5, consider a third member swap from a '55.2 to '62 1/2 ton axle. It is a bolt in to your original housing. You'll have 3.90 gears and an open drive shaft.
That is as "bolt on" as it gets for your situation.
You will still have to weld your spring pivots though.
Any other complete axle will require relocating and welding the spring pads.

I'm using the stock rear axle with the original tranny and torque tube. I had the machine shop guy put in the Patrick's 3.55 setup in the rear diff.

my '48 comes with a '70 Impala 10-bolt. May keep it, or may swap for a Camaro Disc rear.

All you had to do was check the Tech Tips link for possible axles.


http://50chevy.freeservers.com/Suspension_Widths.html#Suspension

I went with an 85 Pontiac Firebird rear,although mine's on a 4-link,it wouldn't be difficult(or too expensive) to add leaf spring perches.Plus the width is good.

This sounds like the way I want to go. I would like to keep the original axle if at all possible. So my old axle shafts and everything will fit right in, all I change out is the differential? What do you mean by welding the spring pivots?

Also, I found a 1950 GMC that is similar to mine but is an 8 lug. The rear axle looks the same except for that it has an open driveline, would I be able to use this differential one in my 1/2 ton, and if so would it be worth it because of gears, or would it be better to find a 55-62 one like you said above? It has an SM420 so I would guess it might have pretty low gears.

Sorry about all these questions, you can tell Im new to these trucks.

-Nick

Spring pivots are on your original axle because you have a torque tube. With a torque tube there is one u-joint (transmission end) and the pivot points allow the back axle to swivel when going over bumps and such.
If you put in an open drive you will have 2 u-joints and consequently you will have to weld the pivot points otherwise the u-joint will clash with the rear pivot.
Look at your axle and you will see where the spring joins the axle that there is a pin sitting between the u-bolts which hold the axle and spring together.
If you notice your rear wheels are not centered in the well. That is because with the pivot the axle/wheels can move and they can go forward or backward albeit not much, when you go over the bumps.
Hope this helps.

The GMC you found is either a 3/4 or 1 ton. You really wouldn't want to use that axle, as it will have lower gearing that the 1/2 ton, 4.56 or 5.13.

a 1977 chevy suburban 4x4 12 bolt 1/2T heavy duty rear end
3.40:1 ratio w/ a 292 and T5 Hybrid 5 speed trumac.
has 2.75'' brake shoes.
6 lug to match the front disc.

mounted 2.5 to 3'' rearward to allow the under bed gas tank to fit
BUT
it [i]LOOKS much better this way[/i].
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=587685-R1-048-22A.jpg
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=DSC00366.jpg
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=2748800-R1-045-21.jpg

and this IS HOW IT"s DONE::
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=Scan1_0001-1.jpg

Me too. As far as I know there is no other way to retain the column shift which I don't want to give up.

I used a '78 full size Blazer rear end in Walter. It originally had 3.08 gear in it and I ran it that way with a Saginaw 3 groove 4 speed and it worked very well. It is the right width, has the 6 lug axles and all we did was weld on spring perches. I later updated it with a 4.11 posi unit and went to a 5 speed and like it even better.

is there a more scientific explanation of the reason for welding the pivots on the rear end? if not welded, you end up with three pivot points? and since the unwelded pivot allows the rear to move fore and aft, doesn't that simply mean that the yolk/s will also move the same/with the rear's movement?

Take a hard look at how far that axle could pivot. You'll be beating the crap out of something everytime you start out, or reverse. On an open driveline setup the springs locate the axle in a fixed place, with these additional pivots you effectively loose that function.

i don't know enough to see how much pivot there could be when i look at it. but if i imagine it with a protractor, it seems as if it'd have to pivot 30degs or more. but as i said, i don't know enough

On a truck with a torque tube the torque tube locates the rear axle. On a truck with an open driveline something else locates the rear. You don't want the rear flopping around. It will break parts and mess up your handling and ride.

oh, i understood the t-tube to trans/eng/frame stability issue and i will weld them, bec i'd rather follow experience. i was just trying to understand it, and my brain wanted to see that mo pivots would be mo better, vs mo floppy

I used the rearend out of a '79 Trans Am. There are all types of upgrades for this and its posi traction. Be sure to move the spring center bolt hole in the perch 1/2" back before you weld it on, much easier, and that will put your axle back in the center of the wheel well. It changes the rear to 5 bolt but then another thing to do is get a set of front hubs from a 50's Buick sedan and then you will have 5 lug all the way. Then no looking around for wheels. The pinion degree should be around 4 degrees.

If Im looking for a differential from a 55-62, does it have to be 2wd? Or can it be 4wd? All the 4x4s Ive seen in this year seem to have a different style axle, so Im guessing its 2wd only?

-Nick

I found a diff with a 3.08 ratio from a similar year Impala (55-62), will this work in my truck?

-Nick

I did a late 80's firebird. As others said, lots of options this way. I retained factory leafs, welded on a set of spring pads for a trailer axle (same leaf width) made a set of lowering blocks, and then a set of lower plates to hold it all together. I had a tremec t5 behind my 235, used an astro van driveshaft and a crossover u-joint. Easy peasy. Also did a disc brake conversion for the front, GM A body brakes and calipers. Corvette dual master, 9" power booster, all went under the floorboards. Retained the factory pedals, stomp starter, etc. Even welded factory shifter from an old 3 speed on to the s10 top loader handle. With the t5, 2.73gears and posi, I was able to leave first and spin the 18" wheels completely into second and still be making power. Freeway speeds were great 65mph @ 2300RPM in 5th. Sold that setup and doing an s10 frame swap. Take a look at my journal in my sig, may have to hunt around (using the numbers on the top and bottom) but you will find it. Works out really slick.

1967 Camaro rear end (67-69)will work.I had to cut the old perchs off and had a friend weld the new ones on.You have to make sure your pinion angle is set right before welding .

If I remember correctly, the Nova/early camaro is about an inch narrower than the later 70/80 firebird/camaro. I put a nova under my 50 and when turning corners it would lightly rub the bed walls. I put spacers behind the wheels to clear. I was not running very large tires. 235/15 I believe. I put a sway bar on the rear also. that helped the leaning. I discovered that a rear sway bar from a mid 70's FB/Cam fit on the 50 almost like it came that way.

Hey Destroyed47 can you email me? I wanna see if you can give me some info on how you used your stock housing and swapped out your pumpkin to link up to a Saginaw 4 spd. My email is sesparza831@sbcglobal.net I have a bagged 1953 with the original drivetrain and I wanna update it to a open drive line

I have a 4x4 s10 zr2 blazer diff in mine

OG_TRUCK, Please note that Destroyed47 has not been on Stovebolt since 2009. He is long gone!

A friend of mine put a Honda Passport rear axle in his 49. he said it was easy to do and you still have the gm 6 hole bolt pattern. the gearing was just about perfect for his T5.
Jay D.