I have a 1999 Checkmate Convincor 270 with stock 454 Magnum 385hp with Gil wet/offshore exhaust. I am currently running a 23 Mercury Mirage plus prop. I drive the boat in Michigan and can get about 68mph at 5000 rpm. Hydromotive props says I should have my rev limiter moved up to 5300-5400rpm and changed the timing and spark curve (through tyler crockett) and use a 23 pitch hydro Q4 x . What do you think about there ideas? Also, Will I benefit or hurt my motor running those rpm's. I would like to see 70 or 71 on the gps...

That Might be all shes got,,,my old boat ran 68 with the same setup and 70 on gps with no passengers... with the setup you have you wont blow it up..
Money is the issue how much you want to spend for 4 mph and dependability?
I would cal the factory and speak w/Steve Coombs in parts (Bills Son) he has a lot of R&D under his belt in all there Models Think he would be the one to ask..
Bob

Thanx Bob, I will give that a shot. This weekend my buddies blown 502 broke down again so it makes me skeptical of modifying anything. I had planned to do a 174 Wiend blower on my boat this week, but am having after thoughts.... what's your take on that..... Bill

i had a 174 B&M on my 97 253 Convincor. we dynoed the motor at 560 + HP. I turned a 27p Hydromotive at 5200 with 5lbs boost. best i saw was 80.8 on the GPS. Ran upper 70's all day. Never had a single problem with that setup.....no surge or idle problems at all. if you are going to go that route i would have it dynoed and properly tuned/jetted. this will insure a reliable setup.

Hi-Perf, If you don't mind me asking? Who did your tuning and dyno work? Thanks, Doug

Bigwilly, how does the boat handle at speed ? It has been well documented that the checkmates run better with Hydromotive IV props. I have an old 251 convinsor, and it is a world of difference from the mirage to the hydro. Last year we were running 79 mph with a 24p mirage. This year we bummped the power to 650hp (NA 572 motor) I will start testing with a 25p hydro 4 blade hope to see 85mph. Where do you guys boat ?

Dean Nickerson Dynoed it and set up the Carb.