Pickup Truck Bed Size Dimensions on Raybuck Auto Body Parts. Cross-reference chart for Chevy, Ford, Dodge, Toyota, etc, pickup truck bed size dimensions.
flips had two widths, small truck and big truck. far as i know the lids, matress and tent are all the same regardless of small or fullsize. the only change to the shell was the length. your flippac was made to fit the length of the dakota.
I measure 78” though. I have the 6’ Bed on my taco (long bed double cab) and it hangs over 4-5”. I can’t find any other early model truck that’s similar to the dodge Dakota it was sitting on.
You could do a little build and turn it into a camper by building a box around and closing off the end. I did that several years ago with an older Wildernest (same idea as flippac but flipped to the side). Here is the link for Bella PSD who did it in 2007. Awesome job. https://expeditionportal.com/forum/threads/flip-pac-camper-build.3702/
Or you could sell and I would be interested, depending where you are!