I have a 1979 pickup, and I want to know what is different between the 78 two headlight style. And what needs to be done to swap them.
I can't help too much with what needs to be done to swap them but it's two totally different generations of truck so I can't imagine it's too easy.
basically the whole truck is different. You would have to mod the fenders to flow with the grille and mod the core support to mount the headlights and grille.
Lots of fabrication. The 2-headlight Hilux grille sits on the front of the hood and fenders making the nose. The 3rd gen 79 truck has sheet metal making the nose and the grille is recessed into it. Also, the 3rd gen hood has a "dip" in it you may have to deal with to get a straight horizon line, or not. Snag dual headlights from an earlier Hilux, a BMW, a VW, or even a 2nd set of round 3rd gen headlights (which I think are larger diameter than all the others). Then you just need to figure out a grille - I'd probably modify one of those that don't have the 4 squares in the plastic. There are some I've seen with just horizontal bars only. Good luck