Thank for the input. The engine package is a 9:25 compression forged piston, 638 rods, Crane 571/556 with a 236/246 @50 with a 114. Rect heads, Air gap intake, holley 850 with 78/83, stock ign sys. (chevy bb 496 stroker). Engine builder and a few others estimate 475/500 hp. Static comp test 170 psi all cyl. Fresh motor, 15 hrs, Im thinking either the exhaust is holding me back or there is NO way I'm making that amount of hp based om my speed in a 3500 lb boat. What do you guys think?????????????

I would expect your boat to run mid to upper 60's unless it is a real fast hull. A friend has a 24 or 25 ft Sunsation with simlar motor maybe not as built up as yours and he runs 67 ish, Smitty

I have dyno figures at the office. 50 HP

Both were done wet on an HP500 carburated version.

I love hearing that! 2 sets of Stainless Marine exhausts are on my Christmas list for Santa already.

Just to be clear that is the diff between gil manifolds and CMI headers. Test was done fo APBA when the exhaust changed on the new HP500 EFI.

???zero to none on stock motor!

I have to think if from gil to headers the engine made more power, then from stock to a much improved flowing system has to be a benefit. I wish I had a dyno. HARD TO BELIEVE that the aftermarket exhaust company's haven't done basic engine package tests with before and after results for the consumer to see.

Here you go.

Yep,
If you can find/afford them, KE's are the best!

We will have the KE's in stock in a month.