Anyone know where I can get the exhaust flappers (butterfly style) that go at inlet of the Silent Thunder system for a 1989 272SR1?

Try cpperformance.com I think they should what your looking for. Hope this helps. mark

What's the point Mine have been missing for years with no known problems. I was going to replace them myself , but figures I would only burn up the new ones
The outside ones are still intact and seem to do the job

I just took off my silent thunder to replace the seal, low and behold I only had two half pieces left. The box itself should stop any water from getting up there. At least in the amount it would take to hit the tubes. So I believe I will not replace them. Outside flaps are good and the baffles are stock (no holes).

Hey Russ,
I'm getting ready to remove my silent thunder swim platform this weekend to replace the seals. How hard was it to get the box off? Can two people do it or do you need three?

Craig

I need to follow this operation.
Mine needs new seals too. Where did you get them? Formula, or is it something I can get elsewhere?

Iggy,
I called Robert Nelems (magicfloat) and he had them shipped directly to me from Formula. $20 for the parts. There is two o-rings that go around the thru hull tips and a "refrigerator-door type seal that goes around the perimeter of the box. Like I said, I'm going to do it this weekend, I'll post the results on how hard it is. I've been told to check the wooden backplane that goes against the transom real good for rot.

Craig

Russ,

My boat has twin big blocks with superchargers and sits quite low in the stern and when I’m out we often have people sitting on the platform or sundeck.

I have found that Stainless Marine have some flappers that can be retrofitted in the hose so I think I will go with some of those.

Thanks for the help.

I would like to hear more about replacing the seals on the Silent Thunder as i have my motors out now so it would be a convenient time to take it off.

Ian T.

Ok guy's, I started this deal just for the gaskets but it turned into a lot more. Craig hit the money right on the spot. Look for rot!!!!!!! I will start the pic's of this project.

Yea!!!

Pics would be great. How many people to remove the box?