I spent a lot of time helping guys turn this era Mopar into street stockers. The best chassis by far is the late B-body cars (Cordoba /Charger /Magnum). While they were a little heavy they had excellent geometry and some parts availability. There have been some 43.5" bars available, earlier B-Body leaf springs bolt right in, and factory sway bars big enough to work. The big help is ridding the car of all the isolating rubber in the leaf spring shock plates, k-frame, and t-bar cross member. 41" T-bars can be used if you weld the sockets into the transmission cross member.

All the bent bar cars suffer from crap geometry and lack of parts as well as crap quality of the k-member. For a unit that was supposed to anchor the entire front suspension system it did a really BAD job. K-member failures are frequent and trying to find a good replacement is about impossible.