[Rare Iron]

Man, this thread is going all over the place - one extreme to the other. Jim @ STS builds a cool product - I KNOW his product well & him - he's a very sharp guy & a good guy to boot. I can't begin to tell you how well I know his products, but I've never had firsthand involvement on his automotive size inserts.

As far as good performance on a more "conventional" type straight-through muffler, exhaust flowpath diameter will mean EVERYTHING as far as sCFM flow is involved. Now going to a large diameter flowpath & controlling the noise is the real trick. You have to use an effective perforation design, & GOOD packing material that will not break down & leave the muffler. With the thread starter here pushing 800 HP, that is going to be a VERY tough nut to crack & come in under allowed dBA limits - maybe impossible. My packing may not be tough enough, but to date I have never heard about a failure on my Cobrapacks. This would be the first.