DAVHAM,

Thank you for sharing your test data with us. It is quite interesting to see the major differance in RPM just switching from one can exhaust to another. Looks like Bison really missed the boat. Since the Bison pitts style mufflers are on back order I called and talked to DA about possibly switching to their exhaust so as not to loose all the RPM. They said they were switching to Slimline pitts exhausts and those on back order will be filled with a Slimline. Although they haven't tried one yet Slimline is saying the RPM numbers will be equivelent to DA's. I'm keeping my fingers crossed for a pitts that will let this engine turn 7000 + with a 22 X 10 after break in.