This question has been asked many times, and I thought I knew the answer. I was planning on leaving 1/2 to 5/8 of an inch on the rear of the cab.

My cab is now bolted to the firewall, that sets the position.

I put the stainless bed on the rear and I added the front of the bed at the tailgate location to compensate for its thickness. Then I scribed a line across the rear of the cab.

So here are my numbers:

The bed is 58 1/2 long.
The front of the bed is 0.060 thick.
From the rear of the cab to the very rear of the frame I have 58 7/8.

This leaves 5/16 inch for that flap at the rear of the cab.

I'm OK with 5/16 if that's what it needs to be. But it does mean that there is almost no room to fasten the cab down into the frame. It will have to be fastened to that "cab to bed" aluminum piece, with rivets or bolts facing into the cab.

Comments please...

Don