Question on exhaust flappers?
 

I have a 1994 Formula F303 SR-1 with twin 454 Mag MPI. One of my internal butterfly flappers is missing. The other three have slight tears and should be replaced. I also have the external flappers on the exhaust tips. The diameter of my exhaust tips are 3 1/2". The modified ss internal flappers are made for 4" exhaust. My question is: Are these internal flappers really necessary? If so, what suggestions do you guys have to replacing the rubber flappers all the time?

Thanks
Constantine

A second line of defense! Not absolutely necessay, but nice if they work. replacements are available the Teague, BAM & C-P performance. I just removed mine as they are a pain to replace and put on the flappers.

The new flappers are a little different from what you now have. You will need to modify them but, they will work.

Your original tips are cast and plated as opposed to the new stainless tips.

I have both on my 93 303. (Internal and external).

Bob

Blown Formula and Bob Oneil

Thanks for the info! I'm going to remove the 3 remaining ones. Those internal flappers are stuck in the open position - most the time. I bought the boat last June. The guy I bought the boat from replaced the exhaust (stock) from engines to back - except the tips. If I keep the boat, next winter I'll build new motors and buy new exhaust system.

Thanks
Constantine