Anyone have experience with those header inserts? http://store.summitracing.com/product.asp?d=8&s=165&p=3464&searchtype=ecat I know the WhiteKnight has them but I don't have quite the motor he does. I'm trying to minimize my exhaust as much as I can but keep backpressure to make some actual power with my almost stock 355. All I've got is flat tops in 76cc heads, Ebrock Performer intake, Edbrock Thunder AVS carb, forged crank, and headers. With the coming S10 body swap I may make new headers running outside my frame rails. Maybe I could just run primary tubes all the way back along the frame to a single glasspack or 8 really little ones /forums/images/graemlins/smile.gif. I have been entertaining the idea of making my own mufflers, seriouslly not like mufflers are anything special, just some formed and welded sheetmetal.