Rear suspension Measurements.

[Canadian1968]

So I am replacing my rear frame rails and both rear spring perches.

I took measurements before we touched anything.  I would just like to know if there if there are any documented factory measurements I could compare to.

My aftermarket perches that I got,  the cylinderr for the shackle bolt to go threw is exactly 1" forward of the factory.  I am able to move the perch back 1/2".  Both sides will be exactly the same when finised , will 1/2 " make any difference to the leaf spring when installed.

[Ghoste]

Some may say no but if it were mine I would hate messing with dimensions the factory engineers had established.  I suupose the only thing affected would be suspension travel upwards.

[green69rt]

Some may say no but if it were mine I would hate messing with dimensions the factory engineers had established.  I suupose the only thing affected would be suspension travel upwards.

Agree, also I think I read somewhere that the rear hanger needs to hang so that the bottom of the hanger is slightly closer to the front of the car than the top.   Reason is as the spring flattens under load it moves the bottom of the hanger towards the rear of the car.  If the hanger is already hanging towards the rear you may run out of travel or some such concern.   Is that clear??  probably not.....

And there are chassis dimensions in the FSM.

[green69rt]

Just looked in my FSM and it looks like 56.93" center to center on the mounting  holes.  Can't be sure because I have a hard time figuring out what the book says and means.

[cdr]

on a leaf spring you always want the lower spring eye behind the upper mount of the shackle.

[Ghoste]

But how far?  Is there not a spec for this in the Mopar Performance chassis book?  Mine is packed away at the mom,ent and I can't check.

[cdr]

[Ghoste]

By that I'd have to say they allow some wiggle room there.

[cdr]

yes they do, that is the car sitting at ride height,for drag racin you want it at about a 30deg angle ,upper ahead of lower.

[Canadian1968]

I have a FSM but it is for a Plymouth . It helps me out with everything else but this sort of thing


According to the diagram a little forwar is not bad then . If I go to far back I may run into some problems

[green69rt]

Charlie, that's just the opposite that I thought it should be, thanks for setting me straight.