Home made adjustable traction bars

Now that I have the 393 in my 68 Mustang I was looking to reduce my 60 foot times from the mild 1.68 to hopefully a 1.50 or so. After some research I came to the conclusion that the cal-trac bars would best suit my needs, just not my budget.

I looked everywhere online that I could think of for some measurements but I only found two websites that listed any, and they were way off from one to the other. I headed down to the track late last year and found a friend that I have been talking to that owns a 67 coupe that he drag races. I looked under his car and sure enough, he had a set. I asked his permission to take some measurements and he said "sure, no problem".
This is what I am trying to emulate:


Here is the measurements that I took for the front plates:


And these are the measurements that I took for the rear plates that will need to be welded to the rear spring plate. This picture is upside down from how they will mount:


I started off making the front plates. I first drilled pilot holes, then bolted them together to make sure that the final holes were correctly aligned.




I then sanded them and painted them flat black.


What I am doing is running solid bushings in the front of the leaf spring. Within that aluminum bushing is a steel sleeve that the bolt goes through and the bushing pivots on. The steel sleeve is wider than the aluminum bushings so that when you tighten the bolt the sides of the spring perch do not touch the aluminum bushing. I measured it and found out I can run a 3/16" plate in that gap that will pivot on the steel sleeve (3/4" outside diameter) on both sides of the aluminum bushing. That is what I ended up making the front plates out of. All of the holes that I drilled in that plate are 3/4" because that is what I needed to clear the steel sleeves and also I am using 3/4" bolts for the rest of the system.

On the part just behind the front bushing, on top of the spring, I am just using a 3/4" bolt with a bushing between the plates measuring 2.72" and has an inside diameter of .750". On the bottom part that has the hiem joint I used a 3/4" hiem joint with 3/4" threads and spacers of .92" on either side of that.

This is a picture of the hiem joint and spacers on the 3/4" bolt, without the front plates. I did this to show how it will sit in between the plates (imagine the plates on the outside of the spacers, but the bolt head and nut will be on the outside of the plates)


Here are the plates, mocked up with the aluminum spring bushing...


And here are the plates with the aluminum spring bushing off to the side to get an idea of how this is working. I also took out the 3/4" OD steel sleeve that the spring bushing and these new plates ride on...




I then removed my springs and replaced the front rubber bushings with the aluminum bushings. At the same time I mounted the front spring plates with the spacers and the hiem joints.




I then started on the rear plates. On those I just had to cut them out and drill one hole, I didn’t take any pictures of that because that ended up going so fast but I am sure that you can figure that out. I had the machinist make me one spacer that was the same width as the hiem joints that I was using because then I could bolt that in between the rear plates as I welded them on to the lower spring plate and I would not need to worry about burning out to grease on the hiem joint and ruining it.

Here is a picture of the rear plate all welded up to the lower spring plate


And here is a picture of the whole assembly, when I got the swagged steel tubes from smiley’s here in Oklahoma City I noticed that it would be hard to rotate them w/o doing something. I went to ace hardware and found a 1” nut, drilled out the threads so that it has a 1” inside diameter and then welded that on to both tubes so that I could put a wrench on it to turn it however much I would like.


Parts List:

2 Left hand thread ¾” hiem joints
2 Right hand thread ¾” hiem joints
2 Left hand thread ¾” lock nuts
2 Right hand thread ¾” lock nuts
2 19” swagged steel tubes (I cut them down to 18 ½”)
2 1” nuts (for the tubes)
4 6” X 6” 3/16 steel plates (for the front)
4 4” X 4 ¼”, ¼” thick steel plates (for the rear)
2 ¾” ID steel tubes, 2.72” long
4 ¾” ID steel tubes, 0.92” long
1 ¾” ID steel tube, 0.88” long (for the mock up on the rear plates)



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very nice work. believe those are knockoffs of Cal Tracs.

Originally Posted by RPM

very nice work. believe those are knockoffs of Cal Tracs.

Thanks, the cal-tracs are what I was knocking off, i just didnt want to use their name to much in this. They make great products and are really helpful, I just couldnt afford their traction bars. I think later on I will try to get their springs to go with this.

that is excellent! I couldn't afford cal-tracs either. If I had seen this sooner I probably wouldn't have used the shelby style bars.

Great write up!

Thank you. As a side note I would like to mention that I moved the front hiem joints down to the lower hole and it seems like my car is reacting better to it there.

so how much did they cost to make?

I have about $100 in hard cash on these. I had the scrap steel that was needed for the plates on either end, and I got the hiem joints for about $15 each.

Outstanding Sir! Bloody Outstanding!!!

Nice work!! This is the type of thing that I am going to be doing on my 64 falcon project. With the economy being what it is, anytime I can save a few dollars and improve the performance of my car thats a win win situation. I will be printing this and saving it. Thank you.

Too funny!

I did this exact same thing a while back.

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