I bought the 3" X pipe system for my 70 Cuda /gen 2 Hemi /auto and it went on like a breeze. I had the TTI headers on already, and I used the offset DR. Diff kit to put a B-body Dana in. Several years ago I put the same system on my 69 Satelite with a 493/auto with the same results. The only cuts we had to make was on the headpipe/collector adapter to shorten the headpipes by about 3 inches.