where do you guys stand on this idea?

Neat idea, but you would probably have to cut the hood. I understand the slant design was to give a low hood-line, with the added benefit of long intake runners. Not sure why they used it in trucks, which can take a tall engine, other than it was already there. Is the 4.0L an overhead cam? If so, the head sits way above the block.

Don't underestimate the difficulty of making custom brackets and wire harnesses. Those can be the show stoppers. Fitting everything in is a major effort. I am sure the manufacturers spend many man-hours on each new design. Today they can use CAD, and they sure pack it in tight. Other threads have contemplated fitting other modern engine into a Dart, like the Mopar 2.4L or 3.8L, but "too tall" is the usual conclusion.