I have a 10 bolt rearend that I am going to use . How do I accomplish this task? Is there a leaf spring hanger kit ? Thanks
I am installing a 350/350 combo so I wanted to change out old coil spring rearend and install a leaf spring rearend not sure how
Olds are similar to Buicks that year, and going from coil to leaf spring requires major changes to the chassis because of the rear kick up. Parallel or tri-angular link with coil overs work, as does GM truck arms.
I agree with @HEATHEN You may be ahead of the game to adapt the Olds control arms, mounts, springs track bar to the replacement rear axle. Generally, in my experience, coils ride better than leaf springs. Ray
From the nature of your question, I'd do a lot more thinking and reading before attempting a swap. There are lots of little things to consider, like width of the rear end and whether your current wheels will fit. Also, do you just want a driver or do you plan to hot rod it. An S10 rear has marginal strength, and the axles are retained by C-clips. If an axle breaks, it can leave the vehicle. Might look at some 8.8 Fords as they are stronger and can be found with positraction more easily than the S10.....it just depends on the width. I'd also consider using coil over shocks with a triangulated 4 bar set up for easier installation. I think that would help you as far as simpler installation.
Is there mechanical reason such as broken, leaking, noise, too low geared or because of the eng/trans swap. ?As posts 5 & 6 state the control arms & track bar are key elements. Otherwise, it will ride much like a early 70s Chev/Gmc pick-up. A friend purchased a '53 Buick Hdt. some years back that a previous owner had "installed" a Ford 9 w/ leafs. The rear spring eyes were actually rubbing the bottom of the frame. Without a track bar, it swayed in the corners like an old milk cow. It's apart now under reconstruction.
Also, since Oldsmobile used this style rear through 1956, there are a few gear ratios available for it, as light as 3.08.
I love this site so much knowledge. I have a bad habit with YouTube. This is just going to be a cruiser I think the triangle 4 link with coilovers sounds cool . Is there a certain brand of coilovers I should be looking at ? Thanks to all
The brand of coilover is less important than choosing the correct sizing. Factors include sprung weight (weight of the vehicle), unsprung weight (weight of the axle, wheels and tires), ride height, mounting point design, and how firm of a ride you desire. Most vendors can size them for you once you have the info, or there are web programs that do it.
I'm pretty sure @HEATHEN is right and that Olds used this rear through '56 prior to equipping cars with the famous 9.3. If memory serves me right they're referred to as the GMC 8.75. I just went through the rear in my '56 Olds last year and I have to tell you, it's a big tough sonuvabitch. It is not like the weak rears under Fords and Chevys of the same years. The pre-9.3 Olds rear like you have is actually very reminiscent of the Ford 9", where the carrier comes out from the front and the axles are retained at the backing plates. Everything about them is heavy-duty, and deservingly so since the cars they were put under were huge. Yes, parts are harder to find for them, but not impossible. You can get bearings and gaskets through Fusick or even some through Rock Auto. I have to be honest, I think the 10 bolt is actually a retrograde in term of strength from the rear that you have, especially if you're still using the C-clip center.
Just put in a newer drop out 3rd member into your case with the ratio you want and have fun with it. Olds rear ends are tough. I doubt you will break it.
Those are great riding cars. Unless you are building an extremely hot 350 there is really no reason to change out the rear. It will handle the 350 and has big enough brakes to stop the car. But if you must change the rear I would use what is there to mount it in there.
Again I catch myself watching to much YouTube thats why I ask here first . Is there numbers on diff to tell me what gear ratio ?
Not sure if it's like the 56 carrier but if it is there should be a letter stamped on the third member that cross references to a gear ratio. This would be well illustrated in the shop manual. I hate being that guys that's like, "buy a shop manual!" but it really does help for stuff like this.
Those cars ride like a dream going down the road. Just get a shorter spring made for it from Eaton or some one and lower it a couple of inches and be done with it.
The I want to change the whole setup because the youtube or Facebook guys say I need to is probably the worse reason to do so you can ever find. That model of Olds rides pretty good in stock form although it may not be Street Kana material. As far as cruising and cross country driving it will work great. It's open drive so if you do want to swap rears you just do what you need to to be able to fasten the replacement rear to your current suspension. As far as lowering the rear the simple way is to hunt down some rear coils from a later model that will fit right and are just enough shorter to give you the ride height you want without compromising ride. Remember that your current rear axle is a 5 on 5 bolt pattern and the rears you are looking at are 5 on 4-3/4. Meaning that you have a different bolt pattern on the rear than the front unless you swap front hubs. The main thing is that if it isn't broke don't get in over your head trying to fix something that doesn't need fixing and quit listening to the bullshit artists .
I have found that the tide of youtube channels is awash with people who have half an idea, little talent, no experience and enough ego to actually put what they do on on there for the world to see. There are, as I say, some exceptions, but they are few and far between.
A friend swapped in a local V8 GMH rear axle into his 47 Olds convertible and used all the OEM trailing arms, coils, ssway bar and panhard bar. There's no need to reinvent the wheel, just ensure that pinion angle is correct at ride height. Tube shocks were added in lieu of lever actions however he didn't cant them over slightly to reduce lateral movement or body roll. He's happy with result and handling. In saying that I swapped an 46 Olds X-member into a 42 Chevy PU and used all the OEM suspension with a 9" and coil-overs. I hadn't added the panhard bar at this stage. Despite close tolerances in photo the long arm suspension articulated well with no frame interference.
I peeled all of the brackets of the housing in my 50 Olds, and welded them to a 9" Ford housing. There is a vast assortment GM intermediate springs that bolt in with the original hardware. Pictures when l get home later today.
I do think some of the ideas above are worth thinking about. I'm not sure just how your stock set up is made. Since it has coils and trailing arms, the simplest thing would be to use the trailing arms, and maybe convert the springs to coil over shocks. The thing about the stock olds rear end, is that its probably difficult to get parts for....and it probably doesn't have positraction. I don't know if you can even get a posi for it. Which ever choice you make is going to be a matter of solving some type of problem ($). What gear ratio is your stock Olds rear end? My suggestion would be to get a good 200R4 or 4L60 (or late 700R4) transmission and sell the turbo 350. That will give you much better gear ratios in the transmission.....lower first gear and higher high gear. Install them in your car and leave the stock rear end and suspension in place until you can drive the car and see how it suits you. If you aren't happy with the olds rear at that point, then consider making those changes. You will aquire more information and more opinions as time goes by, and can then decide if you need a different gear ratio or not...and different suspension/or not. Get the engine and tranny in place first though before jumping into the rear stuff. Trying to do too many things at once causes projects to sit. Doing it in stages allows you to drive more and enjoy more.
[In saying that I swapped an 46 Olds X-member into a 42 Chevy PU and used all the OEM suspension with a 9" and coil-overs. I hadn't added the panhard bar at this stage. Despite close tolerances in photo the long arm suspension articulated well with no frame interference. View attachment 5550701 [/QUOTE] Interesting. I have the trailing arms and stuff to do that rear end treatment to my ‘33 Ford pickup. I have coilovers and also coil springs (to make it to an earlier period). Very cool, FE el free to post more pictures. I agree with Ekimneirbo, get the engine and trans in and run it with the current rear end. It’s a well designed, good riding, tough old rear end. If it works ok for your taste you saved yourself a lot of work. Parts are out there to service the Olds rear end and brakes, and you can always post your needs here and someone either has it or can point you in the right direction. Good luck. Post some photos.
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