8.75 Spring perch Relocation Measurements

[OllieDemon45]

I have a stock width 8 3/4 getting ready to rebuilt. I purchased new axles, Powerlok unit, ring/pinion and all the other misc parts to go with it, along with the spring relocation kit.
All parts came from Dr.Diff.
I am going to take the rearend to a local shop that is familiar with the 8 3/4's but he is asking for the measurements for the perch relocation.

Does anyone have the measurements for the new locations? I want to make sure i give the guy the correct information. He is also going to install the gears and Powerlok unit for me.

Any info would be greatly appreciated.

Thanks!

 

[el5dart]

i’d say on a guess its the measurement on center between your frame rails

 

[doug 371]

Depends if you put the boxes in centered or flush mounted to the outside

 

[rowinafour]

I have the 3/4 inch Dr. Diff relocation kit on my 69 cuda. I just was just messing yesterday with the car to adjust the spring height. I will measure the perch locators when I head out to the shop later this morning.

 

[Oldmanmopar]

All the inboard kits move the spring in roughly 3 inches per side. Depends on where you place the front Box/Hanger. But 3 inches is the measurement. So move the perches in 3 inches of their factory location for an a body. 43.02 factory a body spring pad width on housing. So your total width will be 37.2 after moving them each 3 inches.

Keep in mind the spring pads/perches must be turned the same and be level with each other after pinion angle is set. Set the pinion angle and weld the right perch. Then remove the housing, level the pads and weld the left. This will properly preload the left spring when tightening the u bolts with SS springs.

 

[el5dart]

ok dr diff only sells the 1/2 offset shackle spring kit. i was thinking you were mini tubbing your car. i think standard perch width is 43” so wouldn’t you just move the perches in 1/2” per side to a 42” perch width? i would install the shackle kit, install leaf springs and then measure the width of the leaf spring dowel pins to be sure.

 

[4mulas]

I have the 3/4 inch Dr. Diff relocation kit on my 69 cuda. I just was just messing yesterday with the car to adjust the spring height. I will measure the perch locators when I head out to the shop later this morning.

If the op is taking about a true relocate kit these are two very different animals. The relocate moves each spring in about 3". The offset hager kit moves it in 1/2"

If you have the offset kit your perches should be 42” Center to Center

 

[4mulas]

I have a stock width 8 3/4 getting ready to rebuilt. I purchased new axles, Powerlok unit, ring/pinion and all the other misc parts to go with it, along with the spring relocation kit.
All parts came from Dr.Diff.
I am going to take the rearend to a local shop that is familiar with the 8 3/4's but he is asking for the measurements for the perch relocation.

Does anyone have the measurements for the new locations? I want to make sure i give the guy the correct information. He is also going to install the gears and Powerlok unit for me.

Any info would be greatly appreciated.

Thanks!

When you say relocate kit could you describe or show or give the part number of the item(s) you purchased from dr diff. Relocate kits and offset hangers kits are very different

 

[OllieDemon45]

The op is talking about relocate not offset shackles and hangers.

If you have the offset kit your perches should be 42” Center to Center

Correct, that is what i figured as well but wanted to make sure. So in all reality, i could take the stock measurement from the outside of the housing to the center of the mounting surface and move it in 1/2" on each side. Or like you said, center to center is now 42" vs 43".

 

[OllieDemon45]

When you say relocate kit could you describe or show or give the part number of the item(s) you purchased from dr diff. Relocate kits and offset hangers kits are very different

Leaf Spring Perches (Pair) for Mopar, Ford, Chevy/GM

This is what i'm asking about for measurements as described on the previous comment.

Mopar A-Body 1/2" Spring Relocation Kit Offset Hangers & Shackles

This is the hanger/shackle kit.

 

[4mulas]

Correct, that is what i figured as well but wanted to make sure. So in all reality, i could take the stock measurement from the outside of the housing to the center of the mounting surface and move it in 1/2" on each side. Or like you said, center to center is now 42" vs 43".

Yes, if you have the offset kit he sells for 175 you can just have the shop move the perches 1/2" inward each side. It doesn’t need to be all complicated by measuring from the outside of the housing etc, just move em over 1/2" from where they are/the stock location. Make sure they keep the same pinion angle and or reference it to just make sure they recognize that.

 

[rowinafour]

Correct, 1/2” offset kit. For some reason I was thinking 3/4 but that was the MP kit which causes some debate. I just measured and they are 42” center of each pin.

 

[OllieDemon45]

Correct, 1/2” offset kit. For some reason I was thinking 3/4 but that was the MP kit which causes some debate. I just measured and they are 42” center of each pin.

So all i need to tell the guy is move them in 1/2" on each side from how they are now.

Thanks for the help!

 

[OllieDemon45]

Yes, if you have the offset kit he sells for 175 you can just have the shop move the perches 1/2" inward each side. It doesn’t need to be all complicated by measuring from the outside of the housing etc, just move em over 1/2" from where they are/the stock location. Make sure they keep the same pinion angle and or reference it to just make sure they recognize that.

Yup, than is what i was thinking too, but wanted to confirm!

Thank you!

 

[JDMopar]

I'm guessing you bought new spring perches for your guy to weld to the axle tubes for relocation. He will have to sacrifice the old ones to keep from damaging the axle tubes when he removes them. Be sure to tell him to check the hole diameter in the new perches in comparison to the locator pins in the springs. All of the spring perches from Mopar Performance have holes that are too big for stock pins and need a bushing made and welded in before putting the perches on the axle. If the holes in the perches aren't tight to the pins, the axle can shift cockeyed a little and cause problems. Just wanted to give you a heads up if you had never experienced that situation.

 

[Dana67Dart]

Make sure the builder DOES NOT center the pinion by having the perches different dimensions from each end of the housing.

ALSO make sure he knows the axle bearings DO NOT get lubed from the gear oil in the housing. My builder (Even though I supplied the entire section from the FSM) did not install the inner axle seals that were provided as he assumed the bearings got lubed from the gear oil. 1 week and grease all over everything.

and regardless if you use Green or roller bearings INSTALL the inner axle seals