I am trying to put my plan together before I start on the 74 1/2 ton chevy I just picked up. My question is, Does anyone on here know how much you need to Z the frame to keep the crossmember from hitting the ground on these trucks?

 

You need to do a few things first before you go through and Z the frame.

1. Determine what ride height you want. I would set the frame atleast 3" off the ground, and preferabley 4". Do you plan to body drop?
2. Determine what tire and rim you want to run so you can have an accurate OD.
3. Make sure you have adequate tools and supplies. Once started your in deep.

Remove your whole frontend, and your motor and tranny. Go to home depot and get some 4x4 wood to lay the frame on for "ride height", and level side to side front to back. Then make your first cut 4 inches in front of the cab, and if nessacary make a second cut 3 inches in front of that to give a gentle rise to weld support metal too. You want atleast 1/2 the frame to overlap incase of accident.

Usually people find a 2-3 inch Z to do the magic for them. Thats why you have to do you homework for your personal deal. I say a goy laying on 24"s with a stock frame with enough clearence, and a guys with 22's running custom frames.