length of camper special /longhorn bed

[jd4300fel]

Hello,

I am in the process of putting a 69 gmc on a late model
frame and running gear. What I am wondering is how much
longer is the bed of a long horn or camper special?
I am hoping that this would keep me from having to cut the
frame and modify drive shaft length, as well as the tank locations
and brake lines and the list goes on.

Another option would be has any body lenthened a fleet
bed?

Have a great weekend !!