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What normally aspirated engine has highest power?

Old 04-04-2021, 09:22 AM
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Default What normally aspirated engine has highest power?

Does anyone have a recent updated list regarding what the various commercially available N/A engineS produce, power-wise, at the prop?

Thanks!
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Old 04-04-2021, 08:38 PM
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my guess, The Merc Racing:
860hp
565hp
520hp

https://www.mercuryracing.com/engines/sterndrives.html
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Old 04-05-2021, 07:46 AM
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Is there a reason why you would want to make big power NA? There is a reason why Merc put superchargers on anything over 525hp, until these 2 latest offerings. I suspect the 860 is well over $100K. I had a Nordic with a pair of Pfaff 700s in it that were NA and I built a pair of 700hp 540s for an Eliminator cat that were NA, but is about the top end of a NA engine that is going to be boat friendly.

Last edited by snapmorgan; 04-05-2021 at 07:55 AM.
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Old 04-05-2021, 05:04 PM
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I totally wrecked the title of this thread...sorry.

Still looking to repower my 252 Baja someday, replacing the stock 454 with something with more oomph...but still using as much of the same setup as possible with what I already have.
'Black' engines then - 502 Mag MPI has...415 hp at the crank? 496 Mag H.O. has 425 hp?
'Blue' engines - 500 EFI has 500 at the crank? What other 502 block based engines will 'fit' for me?

Thanks again
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Old 04-05-2021, 08:31 PM
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Gen V and VI can be built to near 600cui and make 1000hp N/A. Just takes cubic dollars.
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Old 04-05-2021, 08:42 PM
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Most common sizes on here that we see are 540's, 565's, 572's I believe all those share architecture with the 502 block and mate up to all the standard big block parts....

I'm no expert though, but I do have 565's and stayed in a holiday inn once
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Old 04-05-2021, 09:15 PM
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Originally Posted by bajaman View Post
I totally wrecked the title of this thread...sorry.

Still looking to repower my 252 Baja someday, replacing the stock 454 with something with more oomph...but still using as much of the same setup as possible with what I already have.
'Black' engines then - 502 Mag MPI has...415 hp at the crank? 496 Mag H.O. has 425 hp?
'Blue' engines - 500 EFI has 500 at the crank? What other 502 block based engines will 'fit' for me?

Thanks again
I think you need to be a bit more specific. If I remember, you have a 454 MAG EFI, correct? And you're looking to keep it fuel injected, re-use as many of your stock parts as possible on a higher HP engine while still keeping the Bravo 1 outdrive. Am I correct?

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Old 04-05-2021, 09:20 PM
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572 is probably the biggest practical stroker however the most common is a 540 cubic inch motor . 502 block with a 4.25" stroke with a 4.466" bore . A mild build will generate an easy 500 hp, however a motor is just part of a bigger system. The 502MPI is limiting on the induction side and the factory exhaust manifolds are restrictive. Next what about the outdrive. Im in the same spot you are , I have a 272 that had a bad 502 that is getting a mild 540 . One concern is the ability of the Bravo 1 to last and the stock steering to keep the boat pointed straight without adding hydrologic steering. The headers/ exhaust is no mystery, the intake system needs more flow from either a big carb and matching intake or aftermarket fuel injection. Oh yea the fuel system and keeping the oil cool and clean are two more items that come to mind.
there use to be a popular saying "its not about how fast you want to go but how much do you want to spend "
And insurance, idle quality , intended use , return on investment........
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Old 04-05-2021, 09:24 PM
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Originally Posted by bajaman View Post
I totally wrecked the title of this thread...sorry.

Still looking to repower my 252 Baja someday, replacing the stock 454 with something with more oomph...but still using as much of the same setup as possible with what I already have.
'Black' engines then - 502 Mag MPI has...415 hp at the crank? 496 Mag H.O. has 425 hp?
'Blue' engines - 500 EFI has 500 at the crank? What other 502 block based engines will 'fit' for me?

Thanks again
Repowering your boat will give you a boat worth the same as it does today running....anything Merc under 575 will be NA (600SC is still packaged with Bravo XR for reference) and a Merc Racing 525 can be warmed up to more hp... how big of hp directly correlates to how fast you break drives
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Old 04-05-2021, 09:27 PM
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Double Post
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