[Chevy454]

William: I don't have my copy handy, but does the assembly manual show the tailpipe/muffler welded on the transverse muffler system?

Also, I've read that article Porterfield did on the ZL1, but check this: we ran the chambered exhaust on our Y-Camaro up until a couple years ago, and I went low 12.8s with it...I put a Flowmaster system on it as well as a rebuilt tranny and it didn't gain ET or MPH! Never could figure hat one out?? Anyay, it looks to me like the worst part the chambered system is where it flattens out to go under the crossmember...