1972 K5 Wheelbase after rear lift springs ??

[6600DURAMAX]

So installed a set of 52'' rear 6'' lift springs - it has seemed to shift the axle backward......... current wheelbase is now 105''. I have the ability to shift it with the new spring perches I have but am curious if I should ?

Dont believe the wheelbase will shift when the body weight is added?

It also seems teh spring perches are sill rotated down - even though I rolled the rear to about 23 degrees - did this because driveshaft angle will be about 26 degrees when installed

Need to weld everything down but want to be right first.

[6600DURAMAX]

pics

[6600DURAMAX]

1 more

[kwmech]

Good grief is that spring pack out of a C60? Also measure the center pin, I think the 52s were 27'' and 25'' you may have them in incorrectly

[truckster]

Yikes! That looks like it will ride really hard.

[6600DURAMAX]

Started with 6'' lift springs ( not sure of maunfacturer they are about 6+ years old) ..... needed a 2'' block to match the front. Decided some to just cut some springs to make the 2'' block - I dont see it riding any rougher as they are short enough to not interfere with spring flex.

[6600DURAMAX]

What I read is 52'' springs are centered - 26'' from center of bushing to center on each end

[Richard]

Stock the wheel is centered at the top of the arch. Some do not like that and move the wheel about 1" back which will center it more at the bottom opening. Rear of opening angles back more at rear. On high arch springs the axle can move front to back a lot. I get about 3" front to back with my Deaver springs from full droop to full bump, probably more with the new packs I had made. Just want to make sure wheels do not hit at full bump. A bit of work to determine that, requires disassembly of pack. You can see what I did in my thread.
The rear pinion should be set at the same angle but opposite as the t-case. If t-case 5 degrees down you want pinion 4-5 degrees up. Only exception is if running CV at t-case. Then you want pinion pointing directly at t-case, maybe 1 degree down from that.
No way to judge a spring pack by number of leafs. Do not have any idea where the OP springs came from. The Deaver springs I have for my truck are 10 leafs, They are really soft.
The stock 52" rear packs on my 72 had the pin centered.
One more add- the rear springs set an angle. If you just look at the picture with the higher springs you will see why axle is moved back. Many lift blocks move the lower pin forward for this reason.

[6600DURAMAX]

Thanks Richard... you have a hell of a build for sure. Appreciate the help. I'll probably leave it where it is til it comes back with the body then decide if I want to move it since I have the option with the adjustable spring perches.