factory basline height

[chris989]

Hello,

I am in the process of lifting my 1989 2500 4wd.

Does anyone know what, if any, factory measurement might be available to determine if my truck has sagged?

maybe axle hub to fender opening???

or axle to bump stop??

My concern is if i purchase 4inches, and my truck has sagged over the years, I might net 5 inches and not be able to get in my garage.

i do not need the 4 inches of lift , but that is the height of new springs for the rear at 56".

Thank you,
Chris