I changed from gill exhaust and went to stainless marines with a higher pipe system. I probably gained another 5" in height off the manifold. Do I still need the flaps in the tips ? I have rubber flaps on the end of the tips also. Any experience with removing ? I belive I am loosing some power.

we removed the internal flappers on mine when it was stock years ago .they were leaking so we took them out and welded up the holes where the pins went thru. i have 3 seasons on 600+hp 540s with gil exhaust and the same tips with just the outside flapper. no issues .

Any increase in power or air flow that you noticed?

no difference