71 and 72 B-body's use the same floors as an E-body. The frame rail connectors need to be modified at the rear frame raill connection point as the B-body frame rail is angled opposite from the E-body.

So, 71-72 B-bodies use the same frame rail connector as the E-body, but need slight modification.

Here we are installing a set of E-Body Plymouth connectors on a 71 RR for one of the guys that works in our shop. Check his website at www.bruceanliker.com