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Thread: Carb Question...

  1. #1
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    Carb Question...

    Hey All,

    I have a 454 that was converted to an HP 500.

    It has a Holley 4150 850 CFM on it, that went to ****
    this past weekend. Blown power valve, float adjustment adjustment is stripped right out of the bowl.

    Long story short, I am looking for a new carb...

    Can anyone suggest a carb that will be pretty much set when I bolt it on..?

    I understand that they are (Can be) difficult to dial in..?

    Please let me know...

    Thank You,

    Jim

  2. #2
    Charter Member # 55 Charter Member Griff's Avatar
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    A Holley 9022 800cfm should pretty much be bolt on and go. It may some minor tweaking, but the stock jetting should be very close. That is the stock carb used on the HP500.
    The 850 you had was on the large side for a 454.

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    Can you tap/rethread the the float adjustment? Just an idea....

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    I just put a marine edelbrock on mine, perfect right out of the box and they are very easy to adjust if needed
    Want2gofast likes this.

  5. #5
    VIP Member VIP Member MILD THUNDER's Avatar
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    or just buy a replacement bowl and a new power valve. Shouldnt cost much, maybe 50 bucks. The HP500 was a a 502 engine. The HP450 was a 454. Really no way to convert a 454 into a HP500. But you can make a 454 into a HP450 with the proper parts. The HP450 pretty much used the same cam, intake, carb, heads, ignition, etc as the HP500. Just different blocks.

    Stock jets in the HP 450 with the holley 800, were staggard. They used #75 and #83 in the primary, with a powervalve. #89 and #90 in the secondary, no powervalve.

    Now, if you are planning on saying the heck with it, and just want to buy a NEW carb, I'd call Patrick at Pro systems carbs. Its really not much more $$ than a off the shelf holley, but the carb will come with nice hardware, and tailored to your engine. Bolt on and go. Like griff says, stock 800 jetting would probably be close though with a stock holley 800.

    I was considering buying new dominator carbs this year. They were roughly 950 bucks each from summit. Prosystems dominator, built for my application, with all nice pieces, were like 975 bucks each. No brainer.

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    Or call Nickerson. I did and am trying to decide if I am going that way. He told me 499.95 plus parts to rebuild my carb and he says they can rebuild anything no matter how bad. He said it will be set up for my particular motors and will have a lifetime warranty. He said if you ever change anything on the motor he will adjust the carb to go along with the changes. I have 454's with holley 850's and he said that 850's are not to big for 454's. Does anyone have any problems with Nickerson?

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    I have no experience with Nickerson or Pro Systems but If your considering spending $800-$1000 I think you owe to yourself to do some research on Willy's carbs..they are very nice pieces IMO..you can change the jet size with the turn of a hex nut on the side of the metering block..he will build it and run it on a Dyno before he sends it..anyone else on here have any experience with them?

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    I strongly suggest that you save a few bucks and bolt on an Edelbrock Marine Carb 750 CFM.

    Once the air/fuel mixture is correct (it will be very close with the Edelbrock) there is no difference between the 750 CFM of the Edelbrock carb and the 750 CFM of a (so called) improved/expensive carb.

    If the air/fuel ratio is correct, your finished. There isn't much that can be done to improve the performance of a modern carburetor!

    Modified carbs are for people who install MSD ignitions and special electrode spark plugs (they also buy snake oil at the county fair!). They must have a lot of money to waste...
    Dennis Moore

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    I put the 750 Edelbrock on mine almost perfect right out of the box and jegs.com had them on sale

  10. #10
    VIP Member VIP Member MILD THUNDER's Avatar
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    [QUOTE

    Modified carbs are for people who install MSD ignitions and special electrode spark plugs (they also buy snake oil at the county fair!). They must have a lot of money to waste...
    Dennis Moore[/QUOTE]

    I have no experience with the edelbrock carbs. I notice they are spreadbore design. Any idea's on how much HP they can support in a 750CFM? I mean I know they flow 750CFM, but, can the fuel bowls keep up say for a 500 horsepower 5500RPM marine engine? Will they starve for fuel in big waves? Are they tunable with powervalves? Do they offer 4 corner idle circuits to help with long duration cams around the docks?

    They seem like a great carb for a 454/330, 454/365, or similar. Just wondering how they would do on a 500HP long cammed 454. And if one was to purchase a small blower down the road, like a 177 or 250, can he bolt a spread bore edelbrock on it?

    My opinion would be to keep the Holley and fix the bowl and be done. The good old Holley DP carb you have will do anything you want it to. Whether you add more power, a small blower, etc. Easily tuneable, and replacement parts are usually a 5 minute ride to any autozone, advance, pep boys, should you need a gasket, powervalve, needle and seat, etc.


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