Best prop for tantrum with stock 454 mag with 365hp
03-22-2012, 05:50 PM
#21
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What you are saying doesnt make sense. I know you built the boat 15 yrs ago but you cant ignore the rpm's he is seeing. Right now he is running a 21p 4 blade at 4200 rpm. Going to 23p will drop him down to 3800 rpm's...Even if you add 300 rpm's for the 3 blade he is still badly underpropped at 4100.
Personally, I think he is down on power (low compression??) or his boat has gained alot of weight. Either way going to a 23p 3 blade prop isnt going to improve his speed or rpms.
Personally, I think he is down on power (low compression??) or his boat has gained alot of weight. Either way going to a 23p 3 blade prop isnt going to improve his speed or rpms.
03-23-2012, 04:59 PM
#22
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What make of 21" 4 blade???? Do you know the drive gear ratio????
Something sounds way off. You should be able to spin a 22-23 prop to the 4600-5000rpm range with a 1.50 ratio drive and 454mag.
I spun a 23 Mirage plus or 22 Bravo 1 to almost 5000rpms on my 24 Outlaw with a 454mag and the 25 AT is a faster hull.
Something sounds way off. You should be able to spin a 22-23 prop to the 4600-5000rpm range with a 1.50 ratio drive and 454mag.
I spun a 23 Mirage plus or 22 Bravo 1 to almost 5000rpms on my 24 Outlaw with a 454mag and the 25 AT is a faster hull.
04-13-2012, 04:57 PM
#24
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So upon further investigation I don't think it is a MAG. The serial number on the block is a 88-91 7.4L bravo. With that being said and a limited understanding of what the x dimension is. Can I run a 4 blade for better cruising or do I have to go with the 3 blade because of the drive depth.
04-13-2012, 05:14 PM
#25
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Just to double check the intake you can take a magnet and put it on the intake and if it is the aluminum one it won't stick. Unless someone swapped intakes that would tell you if it was the one used on a Mag. I have a 454 Mag in my Switzer 250SS. I run a 23p Mirage and spin that to 5000rpm. At 4000rpm I cruise at 50mph and at WOT which is 5000rpm It runs out at 65mph. On the GPS. Listen to ActiveThunder. That is the prop you want if it is a Magnum engine.
06-05-2012, 08:56 PM
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that wasnt a mag motor, its an older 330 hp that was swapped out for the hp500 that shouldve been in it. I looked at that boat and had a deposit on it, but backed out when we discovered the motor swap, 454 mag wouldve been ok, but a 330 hp your looking at a repower to get any performance out of it.
06-06-2012, 03:44 PM
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that wasnt a mag motor, its an older 330 hp that was swapped out for the hp500 that shouldve been in it. I looked at that boat and had a deposit on it, but backed out when we discovered the motor swap, 454 mag wouldve been ok, but a 330 hp your looking at a repower to get any performance out of it.
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