Currently have the old style flappers in the y-pipe(bullhorn) for the silent choice: 1 piece valve on a pivot pin.

The bushings are gone and the hole in the flappers are getting egg shaped. Sure that they would have found their way to the bottom of the y-pipe this year.
Anyways....... The replacements are a complete snap in unit with the flappers now in 2 halves on a rubber hinge. Do these new styles hold up on performance motors?
Thanks

Yes they hold up very well. I assume the thru hulls will be open at speed--right? Sometimes they are a ***** to install on the older pipes. Have a rotary grinding wheel handy to open up the pipe if needed.

Depends on what you call HIGH PERFORMANCE on my boat they lasted about 1 hour. I do run my exhaust pretty hot (almost dry) though. You don't need them unless you like to back up a lot or anchor with the stern into the waves.

Naw, I don't consider my motor High Performance. Thats why I just called it a "performance" motor I have the Merc/ SS Gil exhaust, so plenty of water to cool. Don't want to take any chances of water being shoved back up into the motor in case of that 1 wave that will rock the boat just right. Better safe than sorry. Then there is always the launching aspect.

I just question the ability of the rubber hinge to hold up under normal use. Seems like a part waiting to fail. I did blow out a new set first time out with the ones in the tailpipes, this is why I ask. They were the same build, 2 halves with a rubber hinge. I have the Salisbury end flaps, so those *really* weren't needed.
In quiet mode at docks and idleling, with the occasionally forget to switch to thru hull.

On the old style with the shaft and metal plate, I used to break the plate in half every year. When I finally couldnt find them anymore I put the new style in and never had a problem after that, But I never run the exhaust closed except at idle. Like Tinkerboater said, they have to have plenty of water and a lot of cam overlap would probably hurt them too.

You may be just the guys I'm looking for. Can anyone tell me FOR SURE what the effect installing diverters on my 540 (built almost identical to bulldog but with slightly more compression) with respect to reversion. Would love to be quiet sometimes but not if it messes up "baby's" health. Thanks. --- Jer

You can probably put diverters on almost any motor. With the bigger motors you will just have to make sure to open the exhaust at a lower rpm than a motor with less cubes and HP.