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496 vs 540

Old 05-19-2014, 05:21 PM
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Someone else mentioned "no replacement for displacement" but there is something else to consider......your drives. Bigger cubes make bigger torque numbers and THAT is what kills bravo drives. Whatever you build, consider TQ and consider a higher rpm motor where the torque stays relatively low.

I built 500's into 540's with heads/compression/cam/etc and made 630hp, 700ft/lbs tq fully dressed on a dyno. Killed 2 XR's.......after going to 5 blade props. My hp peaked at 5,300rpms but tq peaked at 4,200 rpms which didn't help matters.
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Old 05-19-2014, 05:39 PM
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A nice 420blower would be a much easier, cheaper alternative and provide a nice bump in reliability and power. I`m with Wookie 100%!
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Old 05-19-2014, 06:08 PM
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I am a huge fan of the Gen 7 496 (obviously) but I see no reason to build stroked 496's from scratch over a 540. (and especially not 496 Gen 7's LOL)

The price should be cheaper for the 540, not MORE. If you price it per HP or CU IN the 540 wins. If it is more, its only $100's of dollars and not $1000's Look at what you gain from the 540 platform in reliability.

Displacement always wins. Especially next year when you want to go 5 MPH faster. Then you will thank yourself for building 540's...

Last edited by Keith Atlanta; 05-19-2014 at 06:12 PM.
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Old 05-19-2014, 06:17 PM
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I'd have to agree. A bigger blower like a 420, 8-71, and a cam swap, you'd be doing just fine. While there is no substitute for cubic inches, its not the end all be all to an engine making good power. My little blown 454's made 804HP and 736FT lbs. It was just a combination of parts, heads/cam, compression, blower, that came together nicely. I've seen blown 540's with poor combinations, barely make that power with the same boost.

Sell off your 177 packages, and pick up a good used B&M 420 or 871 package, a modern hyd roller cam, and go have some fun. With the stock bottom ends, low compression, a nice roller cam, about 6-7lbs of boost, you'll be as reliable if not more reliable (less heat, much cooler air charge), than the stock 525. You should see 650+hp easily. I wouldn't be afraid of the stock bottom end at that power level. I ran the GM steel cranks and dimple rods for years at that level with no issues at all.
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Old 05-19-2014, 09:16 PM
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Originally Posted by t500hps
Someone else mentioned "no replacement for displacement" but there is something else to consider......your drives. Bigger cubes make bigger torque numbers and THAT is what kills bravo drives. Whatever you build, consider TQ and consider a higher rpm motor where the torque stays relatively low.

I built 500's into 540's with heads/compression/cam/etc and made 630hp, 700ft/lbs tq fully dressed on a dyno. Killed 2 XR's.......after going to 5 blade props. My hp peaked at 5,300rpms but tq peaked at 4,200 rpms which didn't help matters.
the 5 blade props helped the drive failure,they dont slip much so the loading on the drive really shortens it,s life.
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Old 05-19-2014, 09:36 PM
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If you are going with a N/A motor minus well build something to make power a 565 is a better choice than a 540. 582 very good choice also if you are staying with a short deck.
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Old 05-19-2014, 09:40 PM
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what bore&stroke combination makes 582 cu in?
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Old 05-19-2014, 09:47 PM
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Originally Posted by mike tkach
what bore&stroke combination makes 582 cu in?
4.6 bore with 4.375 stroke.

Ha, almost sounded like I knew what I was talking about! Bs, I googled it! Lol
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Old 05-19-2014, 10:51 PM
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Originally Posted by nailit
4.6 bore with 4.375 stroke.

Ha, almost sounded like I knew what I was talking about! Bs, I googled it! Lol
What pin height and rod length do you use? The few I have seen torn down the bores seemed to wear prematurely. Not saying it can't be done, but the few engine builders I have talked with frowned on it in a marine engine. This was years ago and technology is much better now.
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Old 05-20-2014, 05:07 AM
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Originally Posted by Rookie
What pin height and rod length do you use? The few I have seen torn down the bores seemed to wear prematurely. Not saying it can't be done, but the few engine builders I have talked with frowned on it in a marine engine. This was years ago and technology is much better now.
When you want a big cubic inch motor it best to go to someone that is known for building that kind of motor they know what it takes to make them work. This kind of builder would be very familiar with the effect an oil ring coming out the bottom of a bore would have because the crank has so much stroke. Alot of guys build maybe 1 or 2 of a certain cubic inch motor who think they know what they are doing and says its a bad combination because things wear out prematurely... Not the case. There are guys that build motors and there are guys that build big motors.
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