[patrickt]

Originally Posted by Jeff Frigo

I have talked to guys in who race A Production cars (see below) in vintage races that swear that these work well with little to no loss in power.

Dynatech Accessories - Auger Style Muffler

I've heard that too. But there have also been threads on here where guys have tried them and said just the opposite. I also suspect that the psychological force of "believing they work," after you've gone to the trouble of buying and installing them, might also come in to play. I know I had been around more than one Cobra that just plain hurt my ears (from both outside the car, and inside) so I dealt with the issue when SS was fabbing the pipes. I really like their "quieter pipes" on my FE, but it's going to cost him a couple of bucks. On the other hand the auger inserts are only $15, so WTF, he might as well give it a shot I suppose.