have 355 motor producing around 400hp shorty headers ceramic coated 2.5 pipe all the back to the end of the tranny a 3 inch y pipe to a 80 series crossflow flowmaster and dual 2.5 out. it sound restricted.

 

a straight through muffler is the way to go. some examples are magnaflow, dynamax race bullet, or slp loudmouth

 

I founded is the Dynomax Ultra Flo Welded Mufflers Prt#17536 is a 3 inch in and out dual.

 

SLP LM1.

Kinda loud, though, considering that it's actually just a straight pipe.

 

I have a Ultra flow round 3 1/2" straight thru. Best flow but very much noise. Especially with FI.

 

Corsa is a straight-through design and isn't nearly as loud as the other straight-through mufflers out there. Check my FQuick for a sound clip.

Corsa is not cheap, but as it is with most engineered products -- you can have it (sound) good, (flow) fast, or cheap -- pick two.

 

dynomax bullet FTW!!