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Another 250 Holley Supercharger Jetting question?

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Old 03-24-2008, 11:06 PM
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Default Another 250 Holley Supercharger Jetting question?

OK, I have read every thread concerning supercharger carb jetting and have determined my question has not been addressed. I am in the process of installing Holley 250 superchargers on stock 502 mag motors using a SINGLE Holley 850. Seems most everyone is using dual carb setups. I would rather feed one carb rather than two given fuel prices! I have been told a single 850 will work under low boost situations(4-5 lbs) with larger jet settings. I was planning on ditching the power valve and going with .98 jets all around. Does anyone know if this will work? I am more interested in dependablity, blower whine, and raising the "cool factor" than making huge horsepower. Thanks...
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Old 03-25-2008, 07:28 AM
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Call Nickerson or someone with SC carb experience. I think you need those power valves.
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Old 03-25-2008, 12:12 PM
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A very close starting point will be 88 primarys, and 96 secondary with 10.5 power valve on primary and block of secondary. Most of ours here at the shop end up there and are just a little fat. Have set some of them at 88/94. Makes for a pretty neat set-up. Email me if you have any questions.

Steve
www.cathouseperformancemarine.com
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Old 03-25-2008, 06:18 PM
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Thanks for the advice. I guess I will keep the power valve. I was going to remove it because I have heard a single backfire will destroy it. I can see where the power valve would make it idle much better, right? Thanks again. We are going with your recommendation. Bob
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Old 03-26-2008, 01:22 AM
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Just checked mine and that is spot on advice. I run 86 primary with 96 secondarys on a 509ci. Nickerson 960 carb set up.
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Old 03-26-2008, 02:50 AM
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I think a Dominator carb would be a better choice.

I would send the carb you have to Nickerson and it set right. They can massage it to flow more cfms and will get it dialed in real close, if not perfect. Well worth the $$$.
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