I recently received an inverted pitts Bisson muffler for my 3W-35. Muffler looks great and fits perfectly. Only problem is the engine runs 500 RPM less with the Bisson when compared to a normal downdraft muffler. Both mufflers have (2) 5/8" OD exhaust tubes but the Bisson muffler has the ends of the tubes rolled inward. Does this restrict the engine's performance in any way? I'm thinking of cutting the rolled portion of the tubes off of the Bisson muffler in hopes of gaining the 500 RPM back. Any of you out there have had this problem or can think of any reason not to cut the rolled ends off??

Ryan