From my experience the front suspension of AD trucks should only be modified using a IFS kit designed for that application. Having done a subframe on a 54 I say this from experience. I made it work and it is cheaper but not easier when you take into account the extra time needed to fab and refit everything. The 73-87 suspension is probably the worse option for these trucks as the wheels will be too far out and nothing you can do will make the truck look right. There is only so much back spacing available and the truck will have to be set a ride height equal to or higher than stock to clear the rubber. One possible solution is to section the cross member to remove the extra width but then you are getting deeper into custom fabrication.
The camaro or F body subframe option is good but again you will have a fender/tire clearance issue unless you keep the ride height at stock level.
If you are restoring the truck and sticking with the 6 banger then just redo the original suspension and add power steering and disc brakes. If you are hot rodding it then the IFS kit is the way to go.
