How to shorten a 1965-1972 F100 long bed frame and assembling a 1957-1972 shortbed flairside bed.

Sourcing the components to assemble a pickup bed using new parts has never been easier. Whether swapping out from a long wheelbase chassis to a short or Fleetside for Flare, all the sheetmetal and related components are available to get that old pickup in shipshape thanks to LMC Truck.
In fact, the plans for our '71 Ford F-100 project included both of those changes, with the shortbed conversion already handled courtesy of a Shortbed Conversion Kit from Classic Performance Products (CPP; PN 6772LBFSK).
With the foundation laid, we contacted LMC Truck with a laundry list of items necessary to build up a new Flareside box. Assembling the components is fairly straightforward but there are a few things that help keep things "aligned." Many of the components rely on one another in order to attain a square assembly. Cross sills straddle the framerails and provide support for the entire affair. The fenders bolt to the bedsides, which then rests on two perimeter bed wood planks. The front bed panel attaches to the two bedsides and rests on the front cross sill. Out back, the tailgate is flanked by a pair of hinges. If any of the panels are out of square, misaligned, or racked, fitment of the rest of the components suffers.
We started the bed assembly by mating the bed side panels with the rear cross sill, held loosely in place as well as a few carefully placed spacers to hold the panels off the other cross sills until we're ready to install the bed wood. The front panel requires attachment to the bed sides by either hardware or spot welding, but it doesn't come ready for either of those operations. For now, we'll be using one of the threaded fasteners at the top of the stake pocket at either side that it does come equipped with to mate the three panels loosely together. Fenders were added next and we hit the ground running. CTP