The previous owner of the truck was going to chop the top, you can see the marks if you "enhance, zoom in, enhance more".
Current owner, my friend, is going to keep the roof line stock, but the truck will be low for sure. There's already the upper portion of the grill removed. Gotta raise the bed so the top leading edge flows with the belt-line. Before any of that, he's getting the motor and trans sorted out. Motor's coming from an early Camaro. I hate SBCs with a passion, but I've gotta admit, a 327 Mouse for this build is a good choice.
As for your scarfing jig... The only scarfing jig I know how to deal with involves propping me up at the dinner table to scarf down the food.