Ok I have a hard time explaining this but here it goes...
When I built my Z'd frame I tacked a 2x4 to the front cross that way it kept the Cross member off the ground 2". I built the frame on the ground from there. The body mounts are set to keep the cab off the rails by about 3/8". Not sure what this would add up to for a Z but I would say 6" beings that my front horns are reversed just like yours 04Orange. I had to trim the firewall to clear the dist. Also cut 1 5/8" off the rockers.
I still haven't figured out what to do for a hood. The best I can figure is probably a 2" or 3" cowl hood. But... I may have the wife talked into a Blower and then will just stick it out through the stock hood
Good luck with your build and it looks great!!!