I was thinking about doing a body lift on my 94 crew cab f350 7.3 idi factory turbo, looking to get some extra clearance for an upgraded down pipe I don’t really want to modify the firewall. All the kits I’ve found online say they’re only for the gas trucks has anyone done a body lift on an obs 7.3? Is there any reason the kit’s wouldn’t work on a diesel?

 

I believe lifting the cab causes the engine to hit the firewall. I know it sounds counter-intuitive, but that's why they say it won't work.
Why don't you want to modify the firewall? It doesn't take much, and noone will ever know. Most of the issue is the seam sticks out too far, flatten the seam and pound it a bit back where the pipe goes through. Much quicker and cheaper than a body lift. And you won't have to deal with lifting the bed to match, or adding steps because now its too high for the old lady to get in, or wreck your back lifting everything that much higher to get it into the bed.

 

a body lift causes all kinds of issues.
fan no longer sits in radiator shroud. you will need to remove the shroud, which will cause cooling issues.
transmission and 4X4 shifters will need to be modified to work.
bumpers will have to be raised or it will look goofy.
brake lines will have to be extended.
steering column may need to be lengthened.
unless you use grade 8 bolts, you take a good chance of the body or cab being knocked off in an accident, or falling off when the cheap bolts supplied with most kits break.
if your body mount perches are not in excellent shape, they will fall apart real fast due to the extra stress put on them.

in other words, skip the body lift, they aint worth the aggravation they cause.

this is my 88 with a 4 inch suspension lift: