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496 HO swap for 525 EFI

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Old 10-10-2010, 10:54 AM
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Check w/ Mel Riggs, he is in WI.
Also, El indio on this board is now owner of a large Merc dealership in WI.
Which dealership is this?
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Old 10-11-2010, 12:32 PM
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Thanks for all of the input on upgrading power from a 496HO. I've since been doing quite a bit of research on this. And I think that the comments here about upgrading to forged internals is probably a must. I don't want to have to worry about whether the motor internals will handle the extra power from a Raylar kit or a Whipple kit. And when you start factoring in the labor to re-build the internals, you might as well just spend a little more to upgrade to the 525. Plus, I don't like the idea of tearing the motor apart. Anytime you start doing that it just seems like it's never the same again. So my thinking is that if you are going to upgrade to 525hp, might as well spend the money once, buy the blue motor, and get it right. Not sure how to get hold of Mel Riggs or El Indio. If anyone can help me with that, that would be great. I have spoken with Shipyard Marine in Green Bay (they are a Donzi dealer), and the service guy there sounded pretty knowledgeable. One thing I'd be curious about. With the 2008 Donzi 27ZR that I have, I pull about 3,400 rpm's on takeoff until plan, and 5,050 at WOT. I top out at 72 mph. I'm running a 28 pitch Bravo 1 with 1.65 gear ratio. I think my prop and gearing a pretty good, since i'm getting what I think is the most out of this boat. Assuming I go with a 525, I know I'll get more top speed, but what about rpm's while getting on plane. I'd like to see a little quicker plane time. I would think that with the extra hp and torque, and assuming a re-prop, I should be able to turn a little more rpm while getting on plane. Any thoughts on this?
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Old 10-11-2010, 01:34 PM
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[QUOTE=tomahdonzi;3227855]Thanks for all of the input on upgrading power from a 496HO. I've since been doing quite a bit of research on this. And I think that the comments here about upgrading to forged internals is probably a must. I don't want to have to worry about whether the motor internals will handle the extra power from a Raylar kit or a Whipple kit. And when you start factoring in the labor to re-build the internals, you might as well just spend a little more to upgrade to the 525. Plus, I don't like the idea of tearing the motor apart. Anytime you start doing that it just seems like it's never the same again. So my thinking is that if you are going to upgrade to 525hp, might as well spend the money once, buy the blue motor, and get it right. Not sure how to get hold of Mel Riggs or El Indio. If anyone can help me with that, that would be great. I have spoken with Shipyard Marine in Green Bay (they are a Donzi dealer), and the service guy there sounded pretty knowledgeable. One thing I'd be curious about. With the 2008 Donzi 27ZR that I have, I pull about 3,400 rpm's on takeoff until plan, and 5,050 at WOT. I top out at 72 mph. I'm running a 28 pitch Bravo 1 with 1.65 gear ratio. I think my prop and gearing a pretty good, since i'm getting what I think is the most out of this boat. Assuming I go with a 525, I know I'll get more top speed, but what about rpm's while getting on plane. I'd like to see a little quicker plane time. I would think that with the extra hp and torque, and assuming a re-prop, I should be able to turn a little more rpm while getting on plane. Any thoughts on this?[/QUOTE

You will want to go a little easy while planing if you want the drive to live but once up you will see a HUGE increase in acceleration that will put a big smile on your face!!
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Old 10-11-2010, 01:42 PM
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Which dealership is this?
http://www.offshoreonly.com/forums/g...gnum-mark.html

Mr. Marine in Fon Du Lac(?).
When i spoke to him a few months back, this was in the working... he mentioned it being one of the biggest dealers.
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Old 10-11-2010, 04:13 PM
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Do the 525. I wouldn't touch a jacked up 496, and most others wouldn't either.
+1 for Don Carter. Stand up guy!
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Old 10-12-2010, 07:44 AM
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Do the 525. I wouldn't touch a jacked up 496, and most others wouldn't either.
+1 for Don Carter. Stand up guy!
My thoughts are the same !!
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Old 10-12-2010, 08:37 AM
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[url]

Mr. Marine in Fon Du Lac(?).
When i spoke to him a few months back, this was in the working... he mentioned it being one of the biggest dealers.
Storm,

Any website to MM's new company?


thanks
Mange
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Old 10-12-2010, 09:29 AM
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Storm,

Any website to MM's new company?


thanks
Mange
Don't think it's been updated.
http://mrmarineinc.com/
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Old 10-12-2010, 09:53 AM
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As far as plane time goes... I have a 28 ZX which I know is a different hull, but assuming Donzi didn't totally re-invent the wheel on the 27 then these things just are not really made for quick planing.

The X dimension on the drive(s) is pretty aggressive for a factory setup and the stepped bottom is just not well suited for quick planing.
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Old 10-12-2010, 09:57 AM
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I did the 496HO swap to a 525.

Things to consider. You should/need to upgrade to a XR drive to handle the 525. You'll need headers. You'll need to rewire/replace your electrical harness. More time and $$ than you initially think but You'll pick up about 10 mph.
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