I have a 93 F350 Cab & Chassis, and a 94 F Superduty...
Both frames are 8" tall until it gets to the rear axle hump.
The F Superduty frame is thicker. Not twice as thick, but between 1/16" and 1/8" thicker.
Neither frame is flat top across the reaf axle; they both have a hump on top, and also get narrower top to bottom at the axle. The F 350 frame is 5.5" high at the axle hump, the F Superduty is 6" there.
thank you Phy! i figured this was the case.
this is just what i wanted to know.there was a debate about this on obn a while back,and i never did get the real facts.
you'll building my next truck right now.do a good job,cus in a few years im gunna coppy ya probably lol.
unless of course by then the 2011 f450 6.7l will probably be in my price range.hard to say i guess.i just hate the new styling.