rear suspension ideas?

ok folks doing a little planning on my late model frame swap for my 50 dodge, everything on the frame is going to work great, up to the rear axle, since its a truck frame the frame does not dip back down like a car frame does, and it has leaf springs that mount at the very end of the frame in the back, I could use this as is but it would mean having to cut all the trunk floor out and raise it about 6" to work with the frame as is, which sounds retarded in my brain. I thought about using a set of chevy truck arms which would allow me to redo the back frame clip, or possibly graft the last 24" or so of the original frame so the bumper would mount in the right spot and not have to butcher the trunk floor. Anyone else have any simple rear suspension ideas that could work with this setup? thanks folks.

 

If you can't easily utilize the suspension that accompanied your frame swap, what was the point of selecting that frame in the first place? It seems to me the primary goal in swapping frames is to gain a frame that already has suspension (front and rear) suitable for the purpose.

Maybe you should rethink the frame of choice.

Ray

 

because its 95% there and what i want, it has aftermarket support, 4 wheel discs, a strong rear end, decent front suspension geometry and its a whole lot less work then any other option. now back on track. it seems that the "truck arm" 63-72 gm setup is pretty damn simple. it seems to be a very viable option, however if i were to run these one thing that came to mind was that i would probably have to move them inboard due to the fact that i figure that a gm frame would be considerably wider then the frame i am using and so would the rear end, so that being said would moving them more inboard cause any undesirable results?

 

Seems like it'd be way more headache making new body mounts for a frame that's not made for the body, than to just clip the front suspension on the stock frame and put the new rearend in the stock frame as well...

 

Okay...have it your way. Regarding the GM truck arm suspension...it happens to be one I am somewhat familiar with and using on my '40 Buick Super project.

I am not sure I understand your concern about frame width in your application. The way the "truck arms" were originally installed by GM is what a builder should duplicate.

The axle ends of the arms mount approximately where leaf springs would normally intersect the axle housing. The arms then angle forward to an anchor point that should be as close to the driveshaft u-joint, and it's centerline vertically and horizontally, as can be accomplished within the ch***is dimensions you are working with.

If for some reason, your frame at the rear interferes with an outboard position on the axle housing you could move them inboard a reasonable amount, but the triangulation is one of the key operative features here.

The other thing you need to know about "truck arms". The original GM design was made in an "I" beam style, from approximately 10 ga. steel by putting two "C" channels back to back to form the "I" beam. That was done so that the arm is strong in it's "beam" shape but will (and MUST) twist from end to end. DO NOT use round, square or rectangular tubes.....whether purchased or home made for this application. If the arm cannot twist along it's length something WILL break in a vehicle with a normal range of suspension movement.

At the front, you will need a crossmember strong enough to absorb all the push and pull being exerted by the arms as they, like Ford and Buick torque tubes, transmit all the driving forces to the ch***is. They just transfer it directly to the ch***is instead of through the engine/trans as in the Ford and Buick TT design.

In my part of the world, good used truck arms are not that easy to find, so I bought new ones from Stock Car Products that they make for the roundy round guys. I also bought the axle pads that are made with the angle built in. Not cheap, but very well made stuff.

If you do a search about truck arms you will find at least one lengthy thread on this subject with lots of opinions about these arms, their shape and placement. A substantial number of those posts are mistaken, many are correct. If you decide to wade through that you will have to seperate the wheat from the chaff.

Best wishes with your project.

Ray

 

thanks,
i will be keeping the stock angles of the arms, just as stated before I may need to move them inboard some, as of right now i plan on using stock GM arms and cross member just narrowing it down some. which is what im worried about, moving those 2 front pivot points closer together will make it a bit weaker in my eyes and i am thinking will make the axle a bit more prone to twisting side to side like say on the axis of the pinion. but then again its going to do that in normal driving anyhow. but like you said they use that set up in circle track, and those cars cant be as wide as a 63-72 gm truck can they?

 

You will have to run a Panhard bar either way. So, keep the front truck arm mounts as close together as practical for better handling and ride quality.

 

Did I miss the reason for the frame swap ? This sounds like a giant headache,...What is wrong with the original frame ?

4TTRUK

 

Ray, thank you for reiterating this. I have been trying to get this across to people for years. I am often told that I (MME/pro ch***is builder) do not know what I am talking about. It is nice to see that someone else "gets" it.

The laws of physics ALWAYS win.

 

You get used to it...

I LOVE those kits that have truck arms mounted to the single, bolt-in round tube crossmember. 'Course you can get away with just about anything when you are only idling around the fairgrounds...

 

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To lower the rear of the truck frame, all you have to do is c-notch the rear of the frame. And in so doing, you will be able to lower the rearend of the frame the number of inches to match the original frame height when you weld in the notches.

This will also shorten the distance between the leaf spring mounts, and you will need to move the front mounts forward an inch or so to correct the distance between the leaf spring mounts.

Bet you're using an S10 ch***is .... suprised the non-traditional popos aren't all over you...

Regards,
X

 

no not an s10 frame, I don't see a frame swap being non traditional.. people have been doing that for years. the car is mainly mopar, didn't plan on doing that, its just how it turned out. now **zzy could ya draw me a picture? I see the *** end of the car getting lifted by lowering the rear spring mounts. and by c notches i am ***uming you mean full C's not the weld in plates they make for lowered mini trucks and such I am going to the junkyard today so i am gonna look out for different suspension ideas while i am hunting the other parts I need for my 55 van. but does anyone have any other ideas for simple coil spring rear suspension? and keep in mind i am on a shoe string budget, so the choices would be limited to what I can find in a junkyard...

 

No offence intended hear but it sounds like you are going to do what ever you want anyway. However I agree with others as to how it could best be done with the least amount of work and cost to you by using the og frame and grafting components to the frame that fits the body... Again No offence intended Ok JMHO

 

1950coronet600hp,

Here is a picture of what I meant. When you weld in a notch (which you might want to do anyway) you can lower the rear section of the truck frame to be more like a car's frame.

This will push the leaf spring mounts a few inches closer together, which you will have to deal with... just move the front brackets forward an appropriate amount.

Regards,
X