Lift kit help?

[Coneboy]

I just picked up a 4" lift kit for my 1980 GMC Jimmy. The rear is springs only- no blocks. My question is: When adding this type of lift to these trucks, has everyone ended up with the same shims? Or is it on a case-by-case scenario? If you've got the same set up, what degree shims are you using? THANKS!!!

[68Timber]

Seems like all the lift blocks have the same taper built into them, but honestly they are going to have different effect on K5 vs K10 short bed vs K10 long bed. I'd start with whatever you have and see if you have a problem.

[Coneboy]

Thanks Bruiser, I was just curious if there was a trend toward a certain degree shim. Thought I might be able to narrow down which shim to purchase and get lucky the first time. Guess I'll just have to go the long route. Thanks again

[Ski-me]

I'd recomend Steel Shims that bolt to the spring pack. Not the aluminum ones. Aluminum tends to get brittle and can break apart...not good. And the aluminum ones I've seen don't bolt to spring pack (pro-comp comes to mind). Just be aware.

Also, with a 4" lift, you may end up with driveline vibration issues. Really depends on truck. But more likely, than not. As a short term fix, you could drop your t-case with a t-case drop kit. Don't use the small, think washer stack you may currently have that is on top of the t-case cross member. They are not strong enough to use as a drop spacer.

Once that is done, your t-case angle should be parallel with your axle yoke angle. That's with the stock driveshaft. With the lift and tcase drop, your driveshaft is also going to be too short so you may have to lengthen it too. Just have to see once installed.