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496 HO manifold restrictor plate removal?

Old 02-19-2005, 11:07 PM
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Default 496 HO manifold restrictor plate removal?

In past threads Raylar has mentioned that the 496 has a restrictor plate between the manifold and riser which would free up 15-20 hp by simply removing it. Has anyone checked into this and actually removed it and if so, what's involved? This to me seems like a fairly simple task to let the 496 flow better and even sound better... What are the pros and cons? I'm bored waiting for spring and need something to do...
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Old 02-20-2005, 06:34 AM
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Default Re: 496 HO manifold restrictor plate removal?

Sounds too easy. Why would Merc put them in there if all it did was lower your HP? I thought I read somewhere on OSO that someone removed them with no positive results.
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Old 02-20-2005, 10:16 AM
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Default Re: 496 HO manifold restrictor plate removal?

i think it was just on the 01 496's after that year they dont have the restictor plate ,I have an 01 thinking about doing it in the next week or so,will let u know what i find out.
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Old 02-20-2005, 11:10 AM
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Default Re: 496 HO manifold restrictor plate removal?

Originally Posted by Dave M
Sounds too easy. Why would Merc put them in there if all it did was lower your HP? I thought I read somewhere on OSO that someone removed them with no positive results.
My understanding is that they prevented reversion. Don't get me wrong, I'm not expecting a big performance increase by removing it. I'd just feel better knowing the restriction was gone and possibly free up 15-20 hp. And if it's simple to do then why not...
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Old 02-20-2005, 11:14 AM
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Default Re: 496 HO manifold restrictor plate removal?

Originally Posted by mwdill
i think it was just on the 01 496's after that year they dont have the restictor plate ,I have an 01 thinking about doing it in the next week or so,will let u know what i find out.
If you get to it before I do, let me know what you find? I have a 2001 Daytona, so I don't know if the motors are 2000's or 2001's? Actually theres a sticker on the PCM 555 ecm that says 2002, which doesn't make any sense to me. Good luck
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Old 02-20-2005, 02:09 PM
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Default Re: 496 HO manifold restrictor plate removal?

Originally Posted by Harper220
If you get to it before I do, let me know what you find? I have a 2001 Daytona, so I don't know if the motors are 2000's or 2001's? Actually theres a sticker on the PCM 555 ecm that says 2002, which doesn't make any sense to me. Good luck
will do, won't be able to run it for another couple of weeks,but i will let u know what i find when i take them off
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Old 02-20-2005, 02:36 PM
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Default Re: 496 HO manifold restrictor plate removal?

I don't know if you will notice any significant improvements by removing them. I did help a friend install a Whipple on his 2001 2 years ago and the instructions had us take them out. He has no problems because of removing them.
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Old 02-20-2005, 02:42 PM
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Default Re: 496 HO manifold restrictor plate removal?

Originally Posted by 28Eliminator
I don't know if you will notice any significant improvements by removing them. I did help a friend install a Whipple on his 2001 2 years ago and the instructions had us take them out. He has no problems because of removing them.
Like I said before, I'm not looking for it to snap my head back once removed. I just want them gone and no restrictions. Since you have removed them before, what exactly do the plates look like?
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Old 02-20-2005, 04:51 PM
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Default Re: 496 HO manifold restrictor plate removal?

10 or 15 horse is about 1 or 1.5 mph depending on the hull
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Old 02-20-2005, 05:35 PM
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Default Re: 496 HO manifold restrictor plate removal?

Originally Posted by mwdill
10 or 15 horse is about 1 or 1.5 mph depending on the hull
Were talking 15-20 hp x 2, so maybe 2 mph in the Daytona. I'll take that in a heartbeat just for taking out some plates. Might even sound throatier too...
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