Brian C,i'm running stock 1.50 ratio,if you can try a merc prop 3 or 4 blade,maybe a 25 3-blade or a 26 4-blade for starter's,like i said i didn't like the way the hydro felt,dave

I have an '04 Prowler with a stock 500EFI, ITS and labbed Bravo 26 4 blade, and it GPS's a solid 73MPH. I've seen 76 with the right conditions. I would have expected at least 75 to 78 with that set up. If I were you I would be out trying some different props. Also, the headers wouldn't be a bad investment.
Just my 2 cents......
JL

Thanks for the input guys. I'm talking to Julie at Throttle Up & we're going to try a different prop & see what happens.

Brian C,did you remove the restictor plate's out of you exhaust,between the riser and the manifold,in the tech section guy's have done that and picked-up a couple of hundred rpm's.dave

Yep, I sure did. It was part of what Whipple wanted done in the install. I'm thinking about going ahead & getting a set of headers for this thing. Like you say it needs to breath.

Brain C,can you post a pic of your boat and engine?like to see it,dave

Dave,
I'll see what I can do. When it comes to me & pics on the computer I seem to have problems.

I have a 2004 260 Prowler w/ a 496 HO also, but am getting only 62 to 63 out of her. It is running on the 4 blade 22 P that came with the boat, and wondering about recommendations to step up to a 26 p 4 blade. A buddy of mine recommended it, but wondering if anyone out there has any more recomendations for prop set up without engine modifications? She also only has 14 hrs on the motor at this time too so I am sure she is not quite fully broken in yet. Thanks, Pete

What kind of RPMs are you turning??? I wouldn't recommend that kind of jump. I can barely turn my non-labbed 26 with any kind of load (4 people, full tank of gas, and water) with a 500EFI. About 46 to 4800 if I remember correctly. My labbed 26 turns about 49 to 5000 in the dead of summer.

jlsnyder26_Sonic,

I'm turning about 4900 rpm with the 22p 4 blade on my 26 Prowler. Thanks, Pete