new owner of 67 dart need conversion help

1500 is too much for a car you are just going to part out, but you have the right idea. The smallest rear in the /6 cars is a 7 1/4, next up in some /6 and 318 cars is 8 1/4, a completely usable rear axle.

You can take your original and the later rear springs apart and "build" a set of mixed leafs to stiffen up the rear, and it surely will have at least "one step up" better torsion bars. That plus the K member, front disc brakes, and get rid of the 67 only idle is a good plan. It's all "bolt in."

I'd look for a cheaper car, but that IS the right idea.