6" lift = what axle shims?

[Rede]

The truck I'm working on has a 6" suspension left, but the rear pinion angle isn't the greatest...
Instead of going higher in the rear with a shackle flip, I was told that I could use shims to correct the angle.

Anyone have any experience doing this?

If so, can anyone tell me what degree of shim I should run to help correct things with this lift?

I've read for other make of trucks with 4" lifts, they were saying 6º shims would work, but I wasn' able to find any recommendations on a 6" lift for an older chevy (1980 K10).
I'm guessing something like 8º or 10º, but I thought I'd ask here first.

[jltait]

IF it is a long bed I would say zero, (I do have experience with the long beds)but this may also depend on the driveline angle. Just turning up the pinion is not a really good way of dealing with driveline angle issues anyway. the angle at the front joint and rear joint should be equal. Meaning if you turn up the pinion x deg's you need to drop the tailshaft of the t-case the same. Now this is all general information. In the end how much correction if any depends on the powertrain length, driveshaft length, and the current operating angles of the u-joints. In some cases with short wheelbases (k5) and this amount of lift the only way to get rid of vibration is to add a CV to the front of the shaft then point the pinion up at the tailhousing of the t-case with a .5-1 deg operating angle. The eliminates the need to have equal angle at both ends.
JLT

[Rede]

The truck currently is a 1980, regular cab, long box, SM465/NP205 with a 6" lift (blocks in the rear) and 39.5"x18" boggers.

The rear leafs are almost flat which I've been told is a sign that they're pretty much wore out.
He went on to say that if I hit a good bump, my leafs could flex or wrap and cause the yokes to connect. He then said without replacing the springs right away, a pair of axle shims would lessen the angle between the rear of the driveshaft and the rear pinion...

When the driveshaft was in place, the yoke on the diff and the yoke/'ears' around the ujoint are almost touching.
I believe there's about 1/8" space between them which I was told isn't very much at all.

Its also a real bugger trying to install/remove the strap bolts as you have to get the yoke in a specific spot to wiggle out the bolts.


I can take pics if it will help explain.

[jltait]

Yeah, pics would be helpful. Do the blocks look like they were purchased or fabricated? Most 6" blocks have some amount of taper built into them.

[drunkbus]

Like mentioned above, it depends on what type of driveshaft you have. Check here: http://www.4xshaft.com/ and click on "tech info"

[TATE228]

I'd like to hope someone wouldent fab a 6" block. That just seems scary to me.