New results :

62 mph gps, with 23 Mirage Plus :-)

Seems to be difficult to reach the goal of 64 :-)

61,5 with a slightly cupped Bravo1 24, better alaorund performance, espesially out of the hole :-)

I know this is an older thread but wanted to bring it back up...

I purchased my 98 271 with 454 Mag/Whipple 2.3...boat ran ~80, 1:65 spinning a Bravo 1-26 pitch with myself & light fuel load but was turning about 5400rpm plus I had to run 93 octane.

I have recently built a 517 (600hp/651trq), running a Bravo 1:50 with the Bravo 1-26 pitch I only get about 65mph/4000 rpm, also tried a Hydromotive Intimidator Q-IV 23 pitch and only getting 61mph/4400rpm

talking to some of the prop shops and they are recommending dropping down to a 20-21 pitch or swapping my drive back to 1:65 gears

I disagree. You are running into another issue here. What are you doing for fuel on the new 517?

Something seems to be wrong here, your rpm is way to low with the Bravo1 26 pich

I have 271 SR1 and do 61 mph with a stock 496 HO Bravo XR drive Bravo 1 24 Pitch 5000 rpm....

Best so far is 62 spinning a Mirage 23 plus... I am running in saltwater though...

You should minimum see 70 +++ 5000 -5200 rpm..

Demon 800 carb, Holley fuel pump set at 7psi

I agree, I just can't figure it out yet

What size jets are you running? I had a similar problem not being able to get RPM when did some reworking. Jets were wayyy off

My 540 EFI will need up in a 271 Fastech once I get tired of messing with people in my 252 with 720HP

Has anyone removed the water tank or any other stuff in the cabin to lighten up the boat a little? I don't use my water system.. Thinking the lighter the hull the the less drive failures.

I added a jl sub sealed enclosure 60 lbs right up front and it didnt affect speed at all,I also removed silent thunder box.Of course no speed gain just more noise,put it back on.Sure is fun trying though.