So I am planning on moving my rear end back 1" for multiple reasons. I keep reading that guys just drill a new hole in the spring perch and move it back. My question is are you also drilling a new hole in the shock plate ? Or are you just shifting the rear end back and leaving the u bolts at a funky angle ? Any other suggestions or methods for moving the rear back ? Thanks.
Moving Rear End Back 1"
- Thread starter MagicMan
- Start date
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TrailBeast
AKA Mopars4us on Youtube
One inch isn't going to make squat of a difference for the shocks and plates.
I drilled a hole in the shock plates as well. But I found what I believe is a problem because the lower shock mount and the upper shock mount are no longer in line. Makes the shocks tricky to get on and off, and I think when the axle rotates on acceleration, it throws the shock into more of a bind.
I'm trying to come up with a workaround.
I'm trying to come up with a workaround.
Inboard spring relocation kit's have holes on the front mount so you can move the whole spring assembly back, but you could use different hangers in the front, but you would probably have to use sliders in the rear instead of shackles.
There has been a few threads here at FABO about the subject. I'll see if I can locate the links.
If they are available, no reason why you can't simply install longer front spring hangers to move the axle back. Now, here's the disclaimer, you need to double check that you have enough driveshaft spline left if your axle is moved rearward.
In other words, no need to shift the axle back on the springs, move the springs, axle and all. You would be surprised how little the rear shackle angle will change by moving it back a inch or less.
Thanks Mike, as far as driveshaft goes I am good there and part of the reason for wanting to move it back is to keep from having to shorten it. After reading those links I am still as confused as before. Seems everybody has their own take on how to do it but spacing the front hanger back is the most common and agreed upon method.
Logan
Well-Known Member
My local spring shop said it was ok to drill a new hole 1" back from the stock hole on the main leaf (only) and reassemble the spring(s). This effectively moved the rear back 1". I now have about 1.5" from the tire to the rocker lip. Tires are 275-60/15. Gas tank gets pretty close to the rear end but it's ok. You would not want to try to exceed 1". I modified the lower shock mount so the shock stayed in the same place; Also, the the rubber hydraulic brake hose mounting point so the hose movement was the same. I may move the rubber bump stops but for now it looks like they're ok. Car is '71 Swinger.
I make a shim pack and place them between the front spring mount and chassis mount point. The pack moves the entire hanger rearward. No need to drill anything.
If I'm moving them a lot, I put longer bolts in the front hanger.
If I'm moving them a lot, I put longer bolts in the front hanger.
Several years ago I had AR Engineering make a set of longer front hangers for me. Beautiful work and the price wasn't bad either.
340doc
Well-Known Member
Check out B body front spring hangers for super stock springs. They are longer because the b bodies use a shorter a body spring.
340doc
Well-Known Member
Are you sure? I have a set on the shelf and thought it was the same when I compared them.
Yes, I tried with some 69 B-body mounts. The pattern is off just enough so that I couldn't drill new holes without overlapping the original A-body holes.
B body SS Spring perches move the eye position back 2" from the std B location. that would be too much unless you drilled a 1" back hole
Keep in mind that the stock B-body (69 plymouth) hanger is already about 1/2 - 5/8 inch longer than the stock A-body hanger.
340doc
Well-Known Member
That's what I figured the OP could do. I matched up the hangers again with the stock A body ones and the difference in spacing is only about 1/8 in total on two of the studs. Just drill out two mounting holes on the car a bit and should go right on.
Thanks for the input fellas. For now I just put a set of perches on with three holes and moved it to the back hole. Left plates and hangers alone. Ubolt angle isn't drastic since I'm using taller perches than stock and 1 1/4 lowering blocks. I like that it left my shock mounting in the factory position. If it doesn't work out then I will move back to the center hole on perch and space the hangers back.
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