489 build critique
02-23-2016, 02:52 PM
#42
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You certainly wont be able to spin a 30 prop with your power, 25 mirage + might be a struggle, mgg I had 630hp aside in a 33 Outlaw and it ran 82-83 spinnin 28 4 blade. I dont know how similar the hulls are
02-23-2016, 03:36 PM
#44
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Thread Starter
from my understanding most these boats with 454 and 502 mags run 28 bravo. Mine came with 454 300hp twins with 25 mirage from factory. I would think my combo would pull 28 considering 454 mag is 365 at 4800ish pulls them fine and we should be 400 with more tq. At 5000 and more below. I need a good solid cam recommendation if someone can offer advice before I finish assembly
02-23-2016, 03:42 PM
#46
Gold Member
from my understanding most these boats with 454 and 502 mags run 28 bravo. Mine came with 454 300hp twins with 25 mirage from factory. I would think my combo would pull 28 considering 454 mag is 365 at 4800ish pulls them fine and we should be 400 with more tq. At 5000 and more below. I need a good solid cam recommendation if someone can offer advice before I finish assembly
02-23-2016, 03:44 PM
#47
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There is a difference between a mirage 25 and the 25 mirage plus Im referring to
02-23-2016, 03:48 PM
#48
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Thread Starter
QUOTE=33outlawsst;4407522]There is a difference between a mirage 25 and the 25 mirage plus Im referring to[/QUOTE]
From what I understand it's got cupping and about 200rpm less pitch for pitch right? Better bottom end less top
From what I understand it's got cupping and about 200rpm less pitch for pitch right? Better bottom end less top
02-23-2016, 03:50 PM
#49
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This should be good, I'll just take a seat on the bench............
02-23-2016, 04:13 PM
#50
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Most definitely, however, I think the issue may be what I see is to be the lack of experience board wise, and maybe across the boards wise, with those heads.
Not knowing those, plus what valve spring open and closed psi's he has, plus retainer to valve seal clearance, but considering the compression, the cid's and the exhaust, I would think the following would get him closer to his goals, and choosing Lunati since that made several happy some days ago:
Lunati 20010721 (for Mark IV)
Hydraulic retrofit roller
272, 280 at .006"
221/227 at .050"
can't find lobe info for .200" duration
.575"/.575" lift
112 LSA
Great mid range torque and power. Likes
2000 RPM stall converter and works
great in towing applications with lower
gearing. Largest for inboard/outboard
performance marine use
Not knowing those, plus what valve spring open and closed psi's he has, plus retainer to valve seal clearance, but considering the compression, the cid's and the exhaust, I would think the following would get him closer to his goals, and choosing Lunati since that made several happy some days ago:
Lunati 20010721 (for Mark IV)
Hydraulic retrofit roller
272, 280 at .006"
221/227 at .050"
can't find lobe info for .200" duration
.575"/.575" lift
112 LSA
Great mid range torque and power. Likes
2000 RPM stall converter and works
great in towing applications with lower
gearing. Largest for inboard/outboard
performance marine use
