I've got a 350 engine, 2 bbl. I'm running heddman headers straight to a pipe then to a glasspack (Cherrybombs), then out to a bit more pipe. Obviously it's dual exhaust. There is no H or X pipe, just two straight pipes with all these things connected. When I floor it I hear the natural popping and stuff from the glasspacks while I go through the gears, but I'm wondering if this setup doesn't create enough backpressure and is a bit detrimental to my performance, or is it alright? Thanks.

Glasspacks create quite high backpressure. Free flowing mufflers will increase performance. It is not backpressure that creates torque, it is high velocity that makes torque. That is the reason for using smaller primary tubes in headers, to keep the velocity up. Once the gases are out of the headers you want them to flow as freely as possible. An H pipe helps this by providing an alternate path for the gases. The gases can go into which ever muffler has the least backpressure at the time.

the glasspacks are very low on the performance scale.you will gain a lot more power by switching to a free-flowing muffler.you are choking your motor to death.i think pat will agree,the dynomax ultra-flos are the best bang for the buck! graemlins/thumbsup.gif

Yeap, UltraFlows are the way to go. But even the less expensive SuperTurbos are a vast improvement.

I've heard good things here about the Summit Turbo mufflers also and great price graemlins/thumbsup.gif