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I've got a 7.4L 454 with a Bravo 1 with 1.5 gears.I'm spinning a 25" Mirage at 4400RPM and am getting speeds of 63-65 max.I've met other people with similar setups who are claiming 72mph.,however, I've never run against them.Should I be seeing more speed than this or are others exaggerating.Thanks for any suggestions.
i have a 21 foot Ultra with the same set up with a three blade23 mirage plus I was getting 70 on my speedo but i wouldnt let it stay wide open long enough to see how fast it would go. Now that it is broke in I have switched props to a 4 blade 21 from Valley prop to improve my hole shot I now have had it up to 68 on the speedo at 4400 but didnt go all the way to 4600 which is optimal for this motor ,Also the speed on the dash is not all that acurate so maybe you are doing better than you think GOOD LUCK
Senator,
I don't know what kind of a boat you have, but I'm sure you should be turning a 23, not a 25. Is it a 365 or a 330? If it is a 330, 21 pitch should be tested on your boat. 4400 rpm is not enough, unless you own a sailboat. Did I say sailboat? Sorry, shame on me, I won't do it again.
Thanks for the responses!Can anyone tell me what I can expect for slippage so I can get an accurate estimate with a speed analyzer.Thanks.
I have a good friend that has a 21' checkmate and also had a 23 pitch mirage prop. We switched to a 21 pitch laser II an picked up a lot of MPH and rpm's . We do about 65 MPH and about 5100 rpm and all from a 350 carb engine.