47-55.1 Origianl Rear suspension or upgrade?

[jdicrescenzo]

I have a 49 Chevy 3100 and have a 235 with dual carb and 4 on the floor. Installing new M2 IFS and 2000 Chevy s10 373 rear end. I am wondering about rear suspension.

Should I be looking at the 4 link rear?

Update the leaf springs to something smoother?

Or original leaf springs and just swap rear end?

I am leaning to original for now. To save on time to drive and cost. As well I am novice to welding so don't want to bite off more then I can chew.

[Rickysnickers]

Probably best to just go with the leaf springs then, and save some money to upgrade later.

[nvrdone]

agreed. ive still got the replacement stock leaves I installed about 45 years ago. does it ride like a new truck? no way but its good for the driving I do.

[mr48chev]

Running the stock springs with the rear axle of choice for a while is cost effective and when you are ready to make a suspension change you don't have any more than the cost of new spring bushing kits tied up in it. They are pretty inexpensive from Rock Auto.
I am not sure that Classic Parts is still selling the spring pads for the axle swap. For the 20 bucks they sure make things easy.

[dsraven]

I'm not sure of the driveline configuration of the AD trucks with a 4 speed. do they have a torque tube driveline like the 3 speed versions did? I'm sure you already know this but the old style rear suspension with the torque tube driveline does not mount the axle to the springs like a newer style truck would. the axle hinges on it's spring mounting pads. this is not something that is difficult to change and, like mr48 says, there are or were brackets available to perform the swap since the axle tube centerline is not inline with the spring center bolt where the axle pad sits. just something to be sure of before splitting it all apart so you have the required parts lined up or prefabbed.
when swapping the axle you will need to cut off existing brackets on the new axle and weld on some new mounting pads where it sits on the springs and possibly some other misc brackets as required. when doing this remember that you are adding heat to a single spot on the axle tube and, like anything else when you add heat unevenly, things can distort and want to stay that way when they are cooled off. I would suggest to do the torch work a bit at a time and allow stuff to cool. better yet, use a zip disc or a diamond blade like the lennox metalmax to remove the large portions of the brackets with little heat invovled, then a flap disc to clean it up down to the axle tube. the nice thing about the metal max style wheel is they don't get smaller as you use them. when it comes time to weld the new spring pad onto the new axle you will find that mocking it all up and snugging the ubolts etc prior to welding will aloow you to adjust things like pinion angle and axle centering until they are right, then tack the pads on while it is all mocked up, then remove the axle for welding so the welds can be done in a more comfortable and accessible setting. when welding ensure the ground clamp is positioned on the axle tube close to the welding area so current is not able to travel through a bearing in the axle which will have you doing a rebearing job later.
post up some pics of what you are working with so we can all see what you're up to and also what an AD with a 4 sp looks like from the underside.

[jweb]

Just stick with the stock leaf springs for now. Replace the bushings and add some good shocks.

Here are brackets mentioned to mount the axle:
https://www.ebay.com/itm/26496844294...SABEgKSN_D_BwE

[dsraven]

if grabbing an S10 axle why not get the whole package. axle, springs, shackles, park brake cables, brake hose to frame and the frame bracket, stabilizer bar, links and frame brackets for that and the suspension snubbers and brackets. that way you will have options when it comes time. you can always use some new bolt on frame brackets from a newer truck as well. possibly something like a ford ranger that uses a spring frame mount that mounts on the side of the frame like the old truck does. no welding that way except for the spring pad on the axle and possibly some shock mounts depending on your configuration plan. dorman sells new spring hangers for several vehicles and the ford ranger is just one that came to mind from another guy doing the same thing to his old chevy. the newer style springs have rubber bushings that absorb vibration and load shock so using a spring from a newer vehicle will give you that plus they are available at the local parts store fairly quickly. if you like the idea some research and planning prior to starting the swap would yield a better outcome. I suggest that you level the truck on stands and then mark the axle center line of the old axle before you start so you know where the new axle needs to sit. since the S10 and ranger are both about the same size as the AD the spring rating would be fairly close to what you may want for a smoother ride. personally I would go with leaf springs over the 4 link, unless you have some plans other than daily driving, just because there are a lot of geometry issues with a 4 link as far as traction etc plus they take some space that is normally open for running exhaust etc. and they also put the cost up. they need a diagonal link or a panhard bar to keep the axle where it is supposed to be side to side. leafs are bolt in and forget, once the original axle placement and driveline angle are done.
just some thoughts to ponder. google 4 link geometry for more info on that, pinion angle ujoint phasing for more info,

[Dan in Pasadena]

Stock springs, the full stack but flipped a limited slip, disc brake 8.8 Ford rearend on top of them. C'd the frame.

[mr48chev]

47/55.1 3100 already has the springs on top of the axle unlike the 55/59 3100.

This is the axle seat that I mentioned in an earlier post https://www.classicparts.com/1947-54...ctinfo/93-317/

This locates the axle in the right spot and sets the truck back at the same ride height it had with the torque tube setup. U bolts can be sourced locally.

Over to the right they have the whole setup with U bolts and shock hangers that runs 139.95 but saves a lot of hunting around and fabricating.

[mick53]

There is nothing wrong with leaf springs. That spring has no idea if it is straight or coiled. I think the issue is with lateral movement and axle wrap. By using harder bushings and a torque arm or CalTracs its easy to deal with. You can add a panhard bar if you want to be really hardcore. I think part of the romance of the AD's is the straight axles and leaf springs. The magic is in the shocks. There has been a resurgence in drag racing in the last few years with leaf springs. The engineering that they can put into modern custom leaf spring is pretty amazing at a reasonable price. I'm running leaf springs, panhard bar and a Bicknel torque arm with a triple biscuit on a Frankland quick change in my 53 3100 with original frame rails. With the 4:11 ring and pinion gear I have 128 different gear ratios available. A new gear set cost about $100 but you can buy them at the track for about $50. Each set gives you 2 ratios. You can change them in about 15 minutes without even getting dirty. The triple biscuit and a carbon fiber driveshaft will take a lot of the shock off the rear end if my foot accidently slips off the clutch. JMHO. Sorry for rambling. Thank you for your time.

[mr48chev]

Mick always blows my mind with his build.

That said, as I said before check Rock Auto for bushing kits as they sell them at a friendly price but make sure the line you are looking on is the correct line for your truck.
The cost of all the pieces to redo the springs, hang the later axle on your springs and new shocks shouldn't be over 150 if you shop right. Maybe a whole lot less if a lot of your stuff is in good usable shape now. That lets you drive it for a year or maybe more while you decide if you want to invest time and money in an upgrade and study available upgrades as in what 4 link kit fits your needs or what the feedback from other folks is. the" how do you like that _________ setup" question posed to other truck owners can get feedback that you can use in choice making.

[cab4word67]

Hey guys, i just did a C3 vette rear swap for a friend on his 57 with a MSft and I must say it is a night and day difference on the ride. Thinking about doing it to my 67 now instead of the A arms and coil overs. We went with 600lb springs and it rides just like a car now. Owner is very happy with how it turned out.

[jdicrescenzo]

Thanks for all the advice. I think I will stick with the original springs. I was worried I would need worry about drive shaft length if I was to swap later. But I guess that is only if I change ride height, which there are no plans for that at this time.

As a Sunday driver and no real track days planned i guess I don't need the upgrade suspension too much.

[mr48chev]

I would suggest taking the spring packs apart (or having it done) and clean up the leaves and spiff them up so that the leaves work smoother against each other and give a better ride. Outside of new spring bolts, (to hold the spring together) paint, a flap disk or two and time it doesn't cost much or take a lot of time to do it but the results can give you a lot better ride.

Then if there comes a time that you want to upgrade with a 4 link or whatever is the suspension of choice at the time it is something you can do at that time.

[jdicrescenzo]

I will give that a try. My engine rebuild is delayed 2 months, so have the time.

[cab4word67]

Originally Posted by mr48chev

I would suggest taking the spring packs apart (or having it done) and clean up the leaves and spiff them up so that the leaves work smoother against each other and give a better ride. Outside of new spring bolts, (to hold the spring together) paint, a flap disk or two and time it doesn't cost much or take a lot of time to do it but the results can give you a lot better ride.

Then if there comes a time that you want to upgrade with a 4 link or whatever is the suspension of choice at the time it is something you can do at that time.

Thanks
I will redo my spring packs this year as they need paint from the fine tuning now that I am lowered. I did remove my new Blistens and found that is where my stiffness was. So I ordered a set of Vikings like in the front. What I was not aware of is that my 12 bolt only has 1-1/4" before it has been hitting the bottom of my wood floor. So now i get to build and raise the floor a couple inches. I have 2-3/4 at the C notch now so floor will have to come up a couple inches too.
So much different from being 25" off the ground to being on the ground, I love it.

[dsraven]

did you notch the frame above the axle? 2 3/4" of suspension travel back there isn't much, make sure to install some good suspension snubbers or get a good dental plan, haha.

[dsraven]

check out a rear suspension snubber from a newer truck, one of those beehive style ones. they take a beating and keep their form. my old avalanche rear snubbers were almost touching the contact points at ride height, when it was loaded and went over bumps you couldn't tell but it must have bottomed on the snubbers lots. I have used the rear snubbers from S10's before as they bolt on easily and the only require a contact platform on the axle. some of the aftermarket snubbers they sell for hot rodders are pretty small and hard, I am sure they do their job but not sure if dental insurance is still required or advised, haha.

[cab4word67]

Originally Posted by dsraven

check out a rear suspension snubber from a newer truck, one of those beehive style ones. they take a beating and keep their form. my old avalanche rear snubbers were almost touching the contact points at ride height, when it was loaded and went over bumps you couldn't tell but it must have bottomed on the snubbers lots. I have used the rear snubbers from S10's before as they bolt on easily and the only require a contact platform on the axle. some of the aftermarket snubbers they sell for hot rodders are pretty small and hard, I am sure they do their job but not sure if dental insurance is still required or advised, haha.

Dsraven, yes I have a C notch and that is were I have the 2-3/4"

[dsraven]

ok, good to know what youre dealing with. I still recommend a good pliable suspension snubber that gets harder to compress as it gets flattened out more, like the bees nest style. they act sorto of like a rubber spring so there is less chance of a hard metal on metal contact which can cause divets in the axle bearings as well as back and dental issues, haha.
again, your truck, you build it the way you want. maybe private message ogre as I think he has 3" above his axle so roughly the same thing. maybe he could give more relevant advice since he has a few miles on his now. check his build thread for pics. camaro axle with leaf springs I think.