NASCAR Truck Arm suspension question.

I'm planning on installing some NASCAR 51" Trailing arms on my 51 Chevy. I'm using a 56 Chevy rear end behind a 235 with a T5. I am putting in a Gambino Notch and will mount the arms on the rear axle so I can mount the bag on the arm forward of the axle and the upper bag mount on the inside of the frame rail. right now I'm just running blocks on the stock springs and the pinion angles must be OK as I get no vibrations at any speed, so my plan is to mount the arms and tack the mounting pads with the rear end still attached to the springs to hopefully keep the same pinion angle when I remove the blocks and springs and just have the trailing arms.

As I'm visualizing the set up with the trailing arms, I have begun to question what will happen to the pinion angle as the bags are inflated or deflated from the ride height? Anyone who has this set up, do you have any problems running at different heights?

Thanks for the help. Bill

 

The angle changes less, with longer arms.

 

I have done this setup many times. In fact, we are doing this on my bosses '39 Lincoln Zepher, right now. So long as you set your pinion angle correctly at your desired ride height, you will be fine. The angle will change as the suspension cycles, during normal operation, and even more when airing all the way up or down, but with a 51" arm, the angle change will be minimal. When you take the blocks out and put the axle directly on the arms, that will change the angle too, slightly. You may want to wait to set the angle until the blocks are out.

 

are you building your own crossmember where the arms attach or building one

 

Boones, you might be in need of a good night's sleep. You just said the same thing twice.

 

Originally I had hoped to get one from CPP like they had used in the Rod and Custom article they did on the Purple Pig, but when I contacted them they said that crossmember was only a prototype and they do not produce it. So I've looked around and I'm going to make my own with 2" square tube.

Gimpy, I was going to tack the arm mounting pads with the rear attached to the springs with the blocks. I figured if the angle was good as it sits with the blocks and springs, then I would be good with the arms mounted at the same place. Also, since these are NASCAR arms, they make adjustment shims so I will be able to fine tune it if I need to.

Thanks for all the help guys. I'm a real novice on this so I need all the help I can get.

 

Sounds like you are on the right track. Post questions as they come up.

 

Have you guys built your own crossmembers? pictures and measurements would be great if you have them.

 

I want to do the same thing to my 54, I have been looking for some old truck arms to get started. I ran across a kit from Jimenez Bros. in the latest issue of Rod & Custom where they do it to a 51 I believe. Might want to check it out.

 

They make reproductions of the original truck crossmember. Shouldn't be too difficult to fab similar to fit your chassis layout.

 

heres a thread i started

http://www.jalopyjournal.com/forum/showthread.php?t=144403

 

gimpy, you are right, I must have been tired... I have thought about buying a repop crossmember and modifying it to work on my set up (my woodie project).. now that I have a 51 chevy, I will be curious to see how you build yours

 

Budd, This is the article that got me thinking of using these in the first place...I have it bookmarked. I have added several posts to that thread. i tried contacting CPP about getting one of their crossmembers modified and they would not do it and at $200 and then I still have to modify it, I figured I might as well build my own.

 

Here's my first reply from a FNG, so bear with me.
I'm starting to get the parts together for a truck arm set up for my 39 Chevy. In doing research I sent a question to Carl's Racing Products. In the reply a Daniel Corker with them mentioned they could supply a cross member if I gave them the frame width and other details. I'm not to that point yet so I thanked him and said I'd get back to him later. If you are still thinking about buying vs building you may want to contact them.
I did not get any prices from him.
His contact is [email protected] or [email protected] Phone listed was (804) 368-8761 Good luck and I'll keep an eye on this thread.

 

I used the stock crossmember and trailing arms in my 47 Chevy pickup, and they worked very well.

 

I got my mounting pads from Carls and looked at his crossmember but at $285 I figured I could make one less than that.

 

2 link kit

 

Cain, do you have any other pics of the front cross member? Who's kit is this and what does it fit?

 

My concern about the kit featured above is flex. The conventional setup from the Chevy truck had arms that are made from two pieces of c-channel, set back-to-back. In that arrangement, they can flex quite a bit. This flex is expected and necessary to prevent suspension bind. The arms above are not capable of flexing without breaking something. The small bushings at the lead-ends of the arms are not helping this, either.

If you are going to have to fab most of this anyway, why bother with a kit? You can (as I have) score the arms for about $100 at the local yard. A cross-member can be had from the donor truck for about $50.

Those c-notches are really small, and the bags are downright anemic too.

Let the board what you are all building, and we will help you select better, and more appropriate components.

 

I wouldn't use that rear, they're notorious for coming apart.

 

Studeboy, that cross member is for '60-'66 chevy c10 and cpp in anaheim sells them. Well under $200 if i remember right.

 

First I've heard of it, but I've only been at this for 25 years.

 

I've wanted to start this thread a while ago.. Thanks guys!

 

Guys, be advised that member Cain is not just suggesting something he found, or that worked for him, he is promoting products that his company sells. Look at his statistics if you need proof.

 

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57 chev axle, bags stock truck arms. etc..

 

Jeff, is that your rearend. how about a better picture of the front attachment points