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Joined: Jun 2012
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okay you smart ones....Help!!! .......just put in a new Holley 770cfm carb on the rebuilt 400 that has a Muthr Thumber Radicle Comp Cam(.490 in. & .475 ex. Valve Lift.). I love the power but am doing a little tweaking since it seems like it is missing or maybe its just loading up and lobing at low speeds. Is that normal??? SOS! The timing is set to stock so maybe that is not good??
Last edited by RoxyDaisyBlue; 02/01/13 12:46 AM.
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Make sure your distrubutor have has the proper set-up & curve to match your cam.
Steve
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Make sure your distrubutor have has the proper set-up & curve to match your cam.
Steve Steve - Could you expand on that please? I have a pretty big cam in my car also and a stock hei dizzy. No clue on how to determine the correct setup.
1968 Firebird 428 4 speed coupe  2011 Camaro 1LT 1988 Corvette roadster 1975 Chevelle Malibu Classic 1984 Harley FLH Shovelhead 2001 Harley Ultra Classic
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If its over 240 duration probly have to increase idle circuits.
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Joined: Dec 2009
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Idle circuits in the carb? Had the carb built by Cliff to the engine/cam specs.
1968 Firebird 428 4 speed coupe 2011 Camaro 1LT 1988 Corvette roadster 1975 Chevelle Malibu Classic 1984 Harley FLH Shovelhead 2001 Harley Ultra Classic
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Roxy,
That lift is not really what determines how the cam is going to work in your car. It has more to do with duration and lobe separation and also timing. Your compression ratio will have alot to do with it as well and ALOT of other things. There is no easy "just change this and it will work better" answer. Sorry. You can't just throw a bunch of parts together and expect them to work perfect. I wish it was that easy.
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The car is running almost perfect!!!! Our next step is to take a look at the distributor " proper set-up & curve" and the timing. Thank you!!!! Yes, putting in that bigger cam requires some tweeking elsewhere.
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69 RA III T/A Auto
69 Sprint vert 3speed ( sold to a new home)
69 350 coupe ( new home in Denver)
69 350 HO 4spd
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Don't know your specs, but as a hint, you're going to want a lot of initial, small mechnical advance (since you're already starting with high initial), and as slow a curve as possible (heaviest springs).
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Do all of the boosters have a rubber boot that the MC pushrod slides through inside the booster?
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