some questions
 

what size of exhaust is on the 4500 and the 5500s? also can a normal dually bed be put on a 4500 or 5500? Thanks

When you say "size" of exhause, do you mean the pipe diameter? If so it is a 4" pipe like the 3500/2500 with the cat and DPF and NOX scrubber.

To put a normal dually bed on a 4500/5500 you would need to have a good amount of modifications to get it to fit, and it would sit up high.

There is a company that is doing it though... Go Big Garage

http://i145.photobucket.com/albums/r...1/100_2927.jpg

thanks for the info.
them bed conversion are probably alot of money

Hope there doing some mods to the suspension, otherwise you be in the emergency room with failed kidney's, that thing would beat you to death, my truck went through the scales last week at 13,740 lbs(truck only). And by no way is it a comfortable ride. Seems like a waste of money to put a bed on it, detune the suspension, for a truck that says 4500 or 5500 wheres the logic in that? I must be getting old.....

flgc