My 1982 F350 was modified to carry a water tank by a fire department. They cut the frame off just behind the rear spring hanger. Could someone tell me the original frame length of this truck? Either from the back of the cab or back of the rear spring hanger. I'm planning on dropping a military trailer bed onto the cab and chassis.

 

I dont know if they would be different or not but is your truck a pick up or a C/C truck?
I would think a C/C truck could have a vary shot or long over hang after the spring hanger.

Just look at a normal tow truck C/C and it has a short over hang then look at a roll back flat bed for cars and they have a lone over hang.
So it may not be an easy answer and guessing you will need to do what you have to to fit that bed to your truck.
Dave ----

 

From the rear leaf spring bracket near the top rivet to the end of the frame is 5 3/4” on my 86 f350 reg cab 8’ box

 

I would say that would be normal for any pick up truck as you can swap beds between all models even for the short beds / long beds as the difference is at the front.
I have a long bed floor on my short bed flare side truck and I had to cut it at the front for the bolt holes to line up rearward.

Again on a CC truck I don't think there is a standard like the pick up's
Dave ----