HP vs Prop/ RPM
09-19-2022, 08:46 PM
#11
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Originally Posted by Smitty275
Currently a stock 454 making 330hp and 375-400ft/lbs of torque. Most likely going to a 565 with 600hp and 700+ft/lbs of torque. So I was wondering what kind of rpm gain per 100hp to expect. I'm going to build it it for max torque and keep the rpm down. 5500 rpm max. Probably less. I want it to live. I'll have enough to worry about keeping the outdrive alive. Fortunately it only weighs in about 3500lbs with fuel, gear and two people.
Going by the 500rpm /100hp I'd be picking up 1300 rpm. I really don't plan on ever spinning it to 6k. Not that it wouldn't be capable with all forged internals. Goes back to wanting it to live a long time.
Going by the 500rpm /100hp I'd be picking up 1300 rpm. I really don't plan on ever spinning it to 6k. Not that it wouldn't be capable with all forged internals. Goes back to wanting it to live a long time.
‘s. They love it.
09-20-2022, 07:23 AM
#12
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Originally Posted by Smitty275
Starting with 330. Ending between 550 and 600. Dart block, 4.25 stroke, etc. Prolly do a 565. Massive torque is the goal. Which naturally leads to decent HP.
Are you starting from a bare block and building all new? Kinda sounds like it. I'd say you could pretty easily top 800HP with a 565, and still be reliable, depending on how you dress it out; carbs/EFI, heads, cam, intake and such. With a 3500lb boat, you're going to have a beast. And I'm guessing you have a Bravo drive, given your starting point and expressed concern about the drive. You're definitely going to find the limits of that drive with a 565 of nearly any build.
Thanks. Brad.
(937)545-8991
09-21-2022, 07:12 PM
#13
Originally Posted by Brad Christy
Smitty,
Are you starting from a bare block and building all new? Kinda sounds like it. I'd say you could pretty easily top 800HP with a 565, and still be reliable, depending on how you dress it out; carbs/EFI, heads, cam, intake and such. With a 3500lb boat, you're going to have a beast. And I'm guessing you have a Bravo drive, given your starting point and expressed concern about the drive. You're definitely going to find the limits of that drive with a 565 of nearly any build.
Thanks. Brad.
(937)545-8991
Are you starting from a bare block and building all new? Kinda sounds like it. I'd say you could pretty easily top 800HP with a 565, and still be reliable, depending on how you dress it out; carbs/EFI, heads, cam, intake and such. With a 3500lb boat, you're going to have a beast. And I'm guessing you have a Bravo drive, given your starting point and expressed concern about the drive. You're definitely going to find the limits of that drive with a 565 of nearly any build.
Thanks. Brad.
(937)545-8991
09-23-2022, 03:14 PM
#14
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Back OP just an example when I went from 330’s to 480 hp’s. Basically the 330 on roids type deal. I went from 23p to 25p mirage props and gained 1,000 plus rpm. Just throwing that out there. 28’ challenger straight bottom V all the way to the transom.
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Smitty275 (09-26-2022)
09-26-2022, 07:54 AM
#15
Originally Posted by getrdunn
Back OP just an example when I went from 330’s to 480 hp’s. Basically the 330 on roids type deal. I went from 23p to 25p mirage props and gained 1,000 plus rpm. Just throwing that out there. 28’ challenger straight bottom V all the way to the transom.
09-26-2022, 12:32 PM
#16
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Originally Posted by Smitty275
WOW, that's a lot. What'd you pick up, 10-12mph?
This is back in early 90’s when running 80 was respectable on the water. 😂.
