2008 38 Fountain EC with 496 HOs( 425hp), Bravo3 X drives...The factory set up has log-style manifolds mated to CMI custom pipes that turn down at the water line.
The boat hits the red line (5K) at 62 GPS mph with low fuel and load. Shogren cupped the props to get it to its max speed. OK, I hate the log-style manifolds, and have to believe they are restricting exhaust flow...Thinking about replacing with E tops, hoping for 50 more hp per engine by letting the exhaust breath, maybe better mileage for crusing, and possibly more top end. (although a propeller change may be in order)
Am I thinking straight? Anybody done this? What are your thoughts?
Carder

There is no reason that you can't install the headers, however, you may need new tailpipes to mate up to the headers. I Seriously doubt that you will get anywhere near 50 hp. I understand that the 496's respond well to new exhaust, but I don't see 50 hp. If you pick up 20-25 hp, that may translate into about 2 mph gain in top end. You may pick up a touch of economy, but I don't think it will be that noticable without changing the programming to account for the headers. Unfortuately, it's not that easy to make these things go a bunch faster.
Eddie