Offset shackles on MP "oval track" springs?

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snailpower

snailpower

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I had planned on doing Dr Diffs offset shackle kit for a 8 3/4 swap on my 72 scamp. In talking with Cass he mentioned the springs I have (MP P4529414 "Oval track" leaf springs) are longer than stock resulting in a shorter front hanger. These springs were installed by a PO not myself so I don't know about them. They seem sufficiently stiff for my intended suspension setup so I wouldn't mind keeping them.

My question, is there an offset hanger / shackle kit that is comparable with these or am I going to have to get new rear springs?



 
Have you tried them yet? If memory serves me correctly they are the same overall length , but the center pin is moved back a 1/4 or 1/2". So the only thing that is different is the positioning of the wheel in the fender. It will move the wheels back slightly. I had a set on my oval racer duster, I bought them new from MP. Best would be to compare them to your existing springs. Please post what you find out.
 
340duster said:
Have you tried them yet? If memory serves me correctly they are the same overall length , but the center pin is moved back a 1/4 or 1/2". So the only thing that is different is the positioning of the wheel in the fender. It will move the wheels back slightly. I had a set on my oval racer duster, I bought them new from MP. Best would be to compare them to your existing springs. Please post what you find out.
Click to expand...

Correct, the overall length of the springs is the same, the front section is different and it moves the wheels back slightly. This is actually similar to what the SS springs do also, it centers the wheel in the wheel opening.

I ran my AFCO springs with an MP offset kit, the AFCO's are set up the same as the oval tracks. I didn't have any issues running the offset hangers and shackles, although I've since replaced the shackles with sliders.
 
The bolt hole in my front offset hangers are the same as those, 1.5 inches to the centre. You could tweak the holes in the spring perches a bit on the axle if you wanted to it around a bit.
 
Ok, so here are the specs.

Mopar Oval track springs, and the AFCO springs I run, have a front section of 20.5" and a rear section of 35". Standard A-body springs and all super stock springs have a front section of 20" and a rear section of 36". Which is why when you run SS springs on a B/E body you need 2" longer hangers, because standard B/E body springs are 22"/36". I was mistaken about the SS springs moving the wheels back, although many drag racers did do that in order to center the wheels to fit taller tires. Had to refresh my memory with some research.

Yes, I know the math doesn't work out. The oval track springs are not shorter overall, they end up being the same length as the standard A-body springs. Overall length varies a bit because of the amount of arch and spring rate, eye-to-eye measurements don't line up with section lengths. AR engineering still makes non-offset hangers for the Oval Track springs that are a 1/2" shorter to keep your wheels in the same spot, but they don't make offset hangers. But using the shorter hangers changes things too, because the springs aren't longer. So, the angle of the rear shackle would change slightly if you used the shorter brackets to keep the wheels in the original spot.

At any rate, the AFCO's I was running with my offset kit fit just fine. I had no issues with everything moving through it's proper range of motion, and actually, the wheels are better centered in the wheel openings than stock.

If you want to get more confused, look at this AFCO chart and take a gander at the overall length spec. Remember, it depends on how you measure it. The overall length listed here is eye-to-eye, it does not match the segment lengths (otherwise the rear segment would only be 32 3/8"!!!). Also, the 20231M's that I run have been discontinued. They were discontinued at EXACTLY the same time the Mopar Performance oval track springs were reissued. While I don't know for sure, I suspect that the 20231M's are in fact the same spring as the oval tracks and there was some kind of licensing issue going on. The specs are certainly the same.

Jegs lists the section lengths for the Oval track springs, as well as the SS springs
Mopar Performance P4529414, Mopar Performance Leaf Springs | Mopar Performance

Afco-mopar.gif
 
Another item I just thought of is to check the size of the rear bushing. I know the superstock springs utilized the larger B & E body rear bushings, but I am not sure about the Oval track springs. To solve the problem I used the abody rear bushings and built a sleeve in the rear spring eye.
 
340duster said:
Another item I just thought of is to check the size of the rear bushing. I know the superstock springs utilized the larger B & E body rear bushings, but I am not sure about the Oval track springs. To solve the problem I used the abody rear bushings and built a sleeve in the rear spring eye.
Click to expand...

The AFCO's and oval tracks have a 1" rear eye just like the B/E cars. You can actually use Energy suspension 2-2117G bushings, they work with the A-body shackle bolts and 1" eye. Otherwise you either need to sleeve the spring eye to use A-body bushings, or the shackle bolt to use B/E body bushings.
 
Wow really good info, thanks! I currently have these springs on my car with the shorter hangers mounted up front that i didnt even realize were aftermarket springs until i took a look.

The next question I have is the front eye size. According to that chart they have 1-1/2" holes. Dr Diff has a spec on his site for 2 different front eye holes one for .5" and one for 5/8. i have had a hard time measuring this short of pulling the bolt out. I am guessing i will have to do that to get this spec.

Glad to know that i can use these with offset shackles tho. I didnt really want to buy new springs if I didnt need to.
 
The spring eye is 1.5", it uses a 5/8" diameter bolt. Pretty much only stock replacement A-body springs use the 1/2" bolt, just about all of the aftermarket springs use 5/8", including the oval tracks.
 
In case anyone finds this thread some time in the future I wanted to give an update. The oval track springs indeed worked with offset shackle kit from dr diff. Bolted up with no drama.

 
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