I remember that the 68 C body cars had a bolt on front frame assembly, but I don't know when Mopar started that practice. Is a 66 still the welded on front subframe or is it the bolt on subframe?

The bolt on subframe would probably be an easier project, you would have to make brackets to attach to the Dakota frame that would align with the C body bolt locations. The C body subframe angles towards the rockers at about the firewall, and actually bolts up to the rockers (if I remember right) at the trans crossmember. The change in the width of the C body frame rails from the front to the back will be a concern because the front 1/2 (including at the trans crossmember) of a Dakota frame has straight frame rails.

The change in width of the C body frame rails is a big concern with the welded on subframe because the two frame widths need to match up at some point to be welded together. Careful measurements will be required.

Given the complexity of the possible differences in the frame rails for what the gains might be, one would have to give some serious thoughts over this. C body disc brakes are not a difficult upgrade, and the C body steering, suspension, and frame structure are very near in equality to the Dakota stuff. It sounds like a lot of work with little improvement.

Swaps into older cars usually gains independent suspension, modern suspension parts, disc brakes and power steering that most did not have available at their production time and those improvements often justified the amount of work required. Gene