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How fast should I be? Am I missing something .

Old 06-20-2021, 06:43 PM
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Default How fast should I be? Am I missing something .

So I have a 31 awesome cat. Has gen 6 454ís procharged. The blocks are basically stock with stainless marine exhaust and 5 pounds of boost at WOT. Bravo out drives 1.35 ratio with 30 pitch props. Iíve trimmed anyway imaginable. I can only get the boat to run 4800 Rpms at 80 mph and thatís all with a half tank and one extra person l. Itís starts to pack air and Iíll I want is the extra speed to drive through it. 1. Should I be faster than 80 2. Should I lower my pitch or 3. Am I just flat out missing something. Any helps is appreciated.
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Old 06-20-2021, 06:56 PM
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how much power do the engines make ?....

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Old 06-20-2021, 07:47 PM
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Originally Posted by F-2 Speedy View Post
how much power do the engines make ?....
That has to be the starting point to the conversation...

454 truck block came as a 230 hp - convert to marine + 5 lbs of boots would only give roughly 308hp
385hp 454 mag with 5lb of boost would potentially produce just over 500hp - a LOT of mph difference in the HP spread potential.

***Short answer/quick/definite answer is throw on a set of 28's and see where that run get you
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Old 06-20-2021, 11:19 PM
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Definitely lower the pitch until you get to 5200.
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Old 06-21-2021, 12:58 AM
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Originally Posted by catman20 View Post
So I have a 31 awesome cat. Has gen 6 454ís procharged. The blocks are basically stock with stainless marine exhaust and 5 pounds of boost at WOT.
Your hp should be in low 500's with that combo, I agree, drop down in pitch and maybe try some different makes of props. I don't think you will see more than mid 80's with that power though.
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Old 06-21-2021, 08:09 AM
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Sounds like you just repowered. What was the setup before and speed?

What props are you running?
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Old 06-21-2021, 11:54 AM
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Thank you all for the responses. The set up has always been the same as for as I know and the motors are 454í mags. Iíve usually do all my motors and maintenance but drive ratios and prop pitches are a little out of my league so far. Reason Iím on here asking the experts. Lowering the props was going yo be my first start but I really wanted options instead of guessing.
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Old 06-21-2021, 12:22 PM
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try a set of B1 28p 4 blade, I ran them on a 38 TG with similar power to yours 500 EFI's and spun them 5150
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Old 06-25-2021, 11:50 AM
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I don't know anything about the model boat you have, but when I had blown 509's I was running a 1.5 ratio bravo 32p bravo's. I would think the 1.35 ratio bravo's with the 30p props is a lot of gear for 500Hp 454's. I am not an expert just my opinion. Like others have said try some lower pitch props and I bet you see better performance.
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