Potentially looking at a transverse muffler setup for my 81. Jegs has a good deal on this Thrush setup: http://www.jegs.com/i/Dynomax/289/89021/10002/-1 I'm assuming that this only lists up to 74 because it doesn't include cats. Any reason other than that that it wouldn't fit my 81? I'm not afraid of doing some cutting/welding to fine tune the fit, just want to make sure that I'm not going to be going through it piece by piece. Thanks in advance!