Moving front spring eyes rearward

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rw@cuda1haub

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Beside being able to install larger diameter tires, advantage or dis-advantage of moving front spring eyes rearward? Whats normal or maximum amount allowed? I have read some of 3/4 or one inch. I think it would move rear hangers to a bad angle?
 
The only reason I would ever do that was if the rear axle was crooked side to side.....and then I'd look for the difference to be in a frame rail or the unibody of the car before I even considered moving the spring brackets. I've just never thought it was a good idea. Beside the bad rear shackle angle, it will also pull the drive shaft out of the transmission tail shaft a little.
 
If a guy was looking to move his wheels back in the wheel well and was in the process of installing sliders, He wouldnt have to worry so much about shackle angle. Pulling the driveshaft out too far would be a concern as previously noted.
 
Racers do that to keep the front of the slicks out of the wheel openings. There are threads here about the subject and Mancini I believe sells extended front spring hangers. 1/2-3/4" makes a big difference.
 
So everybody does it and that makes it cool. Not for me. Not something I'll ever do.
 
Beside being able to install larger diameter tires, advantage or dis-advantage of moving front spring eyes rearward? Whats normal or maximum amount allowed? I have read some of 3/4 or one inch. I think it would move rear hangers to a bad angle?

The "allowed" amount comes from class racing rules, like NHRA Stock & Super Stock. It limits the amount of difference from OEM specs as well as difference from side-to-side. Some racers staggered the wheelbase from side-to-side to gain more rollout, thus giving faster ETs. Made it difficult for good, consistent RTs.
 
The only reason I would ever do that was if the rear axle was crooked side to side.....and then I'd look for the difference to be in a frame rail or the unibody of the car before I even considered moving the spring brackets. I've just never thought it was a good idea. Beside the bad rear shackle angle, it will also pull the drive shaft out of the transmission tail shaft a little.

Agree , will make slightly less weight on the rear wheels too , opposite of moving them forward , like the early afx cars !-bad idea to me , altho some have done it .
 
The "allowed" amount comes from class racing rules, like NHRA Stock & Super Stock. It limits the amount of difference from OEM specs as well as difference from side-to-side. Some racers staggered the wheelbase from side-to-side to gain more rollout, thus giving faster ETs. Made it difficult for good, consistent RTs.

I made a pass in a fairly well known mopar superstock racers 67 belvedere once , he had the front wheels staggered for a starting line advantage and didnt tell me , was dam hard to control without knowing it. I turned the same et as he did tho---------
 
If a guy was looking to move his wheels back in the wheel well and was in the process of installing sliders, He wouldnt have to worry so much about shackle angle. Pulling the driveshaft out too far would be a concern as previously noted.

Looks like it would be if the sliders bottomed out to the rear ----------
 
Beside being able to install larger diameter tires, advantage or dis-advantage of moving front spring eyes rearward? Whats normal or maximum amount allowed? I have read some of 3/4 or one inch. I think it would move rear hangers to a bad angle?

If you're installing tall enough tires to warrant moving the rear axle backwards to gain tire clearance, you're probably going to be relocating the leaf springs as well anyway. Since relocating the leaf springs will require moving the rear hangers to the frame rail (some choose to install sliders), it's really not much more work to move them back to match how much you moved the rearend.

You just want to make sure the hanger is angled back slightly at ride height to allow enough suspension travel without hitting the frame at full squat, over bottoming out forward with the suspension at full droop.

An alternative is drilling new holes in the mounting pads on the axle tubes and shock mount plates to move the axle back a tad.

What size tire are you trying to run?
 
If I just HAD to have "that" big a tire, I would reshape the front of the wheel well before I moved the springs.
 
That's like overhauling the engine when all you need is a tune up. :poke::rofl:

Or it's just another way to accomplish the same thing. I've just never liked the idea of changing the wheelbase. Polish it up however you want, that is what you're doing if you change the spring position.
 
If you're installing tall enough tires to warrant moving the rear axle backwards to gain tire clearance, you're probably going to be relocating the leaf springs as well anyway. Since relocating the leaf springs will require moving the rear hangers to the frame rail (some choose to install sliders), it's really not much more work to move them back to match how much you moved the rearend.

You just want to make sure the hanger is angled back slightly at ride height to allow enough suspension travel without hitting the frame at full squat, over bottoming out forward with the suspension at full droop.

An alternative is drilling new holes in the mounting pads on the axle tubes and shock mount plates to move the axle back a tad.

What size tire are you trying to run?
 
Thanks for the info. 72 Scamp, installing 405 h.p. 360 Magnum, A518, 323 sure grip, just wanting to get all the tire under it I can.
 
Mine are moved back an inch on my b-body. Wouldn't hesitate a second if i had to do it again. More centered in the wheelwell, and room for a 30" tall tire. Re-drilled super stock hangers.
 
Mine are moved back an inch on my b-body. Wouldn't hesitate a second if i had to do it again. More centered in the wheelwell, and room for a 30" tall tire. Re-drilled super stock hangers.

moving them back creates a little less weight on the rear wheels , if u have any traction problems , it aint gonna help !
 
Wish I knew how far the second car has been moved back. 3/4" would be a guess.

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Mine are moved back an inch on my b-body. Wouldn't hesitate a second if i had to do it again. More centered in the wheelwell, and room for a 30" tall tire. Re-drilled super stock hangers.

Sure wouldn`t have helped this !---------]16 x32 1/2'' stones .
moved forward 2'' w/ 002-003 superstock springs , after it was painted , u couldnt tell it , unless beside another one .
 
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