Switchable mufflers Or Silent Choice?

[sleekcraft78]

I have a 98 Nordic with a 454 and through drive exaust. I want to be able to switch to through transom and back. What is the difference between to two? Will the mufflers be ok under a swim deck? Or should I go with the Diverters?

[Pismo]

Get diverters, then you can skip the mufflers and just have straight pipes/tips out the back. You'll get a couple hundred rpm.

[BDMar]

The problem with "Captains Call" systems is the back pressure when they are closed and diverting the exhaut through the prop. This will cause reversion a high percentage of the time. A good muffler type tip through the transom is a better option and eliminate the thru hub exhaust.

[sleekcraft78]

What do you mean by reversion?

[BDMar]

Reversion is what happens when the overlap of the camshaft causes the intake and exhaust valve to be open at the same time. This causes pulses in the exhaust flow. Since water is mixed with the exhast close to the elbow on stock elbows, the pulses bring water past the bend and it then falls down the manifold and is "pulsed" into the cylinders.

[UnionJack]

I have the Teague ST-405.. and they are pretty cool, they quiet the boat down 20db

[Rob Freeman]

reversion = death to the engine mufflers would be me choice have a nice weekend

[wannabe]

I have been researching the very popluar topic of reversion. The reason is that I want to install a captains choice set-up but am worried about reversion b/c the boat has a decent cam in it. Is reversion mainly a problem at idle, when there is no velocity to carry the water out?
I am thinking that if I only use the through the outdrive route when I am off idle I should be OK.
My wife just about $hit when she heard the boat with the new motor and I need to figure something out. I am the ONLY one who drives the boat and most of the time the exhaust would be open, making reversion...less likely anyway.
505 cid
9:1 comp
roller 242/248 @ .050, 112 lobe sep, .566 lift
EMI thunder wet mainfolds
Thanks,
Mark

[cfm]

Wannabee - I'd check for water reversion now as it is. I've seen same type engines with less cam and same exhaust system revert water.

[Bow Tie Omega]

I have a 98 Nordic with a 454 and through drive exaust. I want to be able to switch to through transom and back. What is the difference between to two? Will the mufflers be ok under a swim deck? Or should I go with the Diverters?
Just remember if you go to the switchable, you can still get dinged by harbor patrol for the noise law, they are not considered a muffler. This law is so stupid.

[Pismo]

How quiet do you want it? Switchable thru prop is totally quiet. Muffler tips will still be loud, just not as loud as nothing.