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Need Some Carb/Tuning Help

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Old Mar 30, 2013 | 02:11 PM
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Default Need Some Carb/Tuning Help

BB 454, Holley 750cfm - 4160 carb (just rebuilt), timing set by Lars's tuning/timing paper.

Problem: starts and idles fine but if I try to get it over approx. 1800 rpm she dies out, like it is starving for gas. I believe I've set the floats correctly. It's getting a good shot of gas when I work the pedal. Took it for a short spin, under load, and barely got it back home. It was bucking and heaving all the way back.

I'm not exactly a Holley carb expert but I've tried all I have been able to read on line and I'm running out of ideas. Any help is appreciated.
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Old Mar 30, 2013 | 02:59 PM
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Sounds like a delivery prob. pluged filter, crimped line, pump. Have you checked fuel psi?
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Old Mar 30, 2013 | 03:09 PM
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Yes I have a fuel pressure gauge and the pressure is right on.
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Old Mar 30, 2013 | 03:23 PM
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Most carb problems are caused by ignition!
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Old Mar 30, 2013 | 05:12 PM
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I've tried changing the timing and the same thing happens. idles great and anything above about 1800 rpm I have to pump the throttle to keep it going. I have gas trickling out of the bowls at the screw holes so I'm pretty sure it's getting gas. Seems to starve for gas above idle. Starting to get frustrated!!
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Old Mar 30, 2013 | 05:36 PM
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hmm,
could be the transition from idle circuit to power.
holleys blow power valves.
any backfiring before the trouble?

also could be ignition module
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Old Mar 30, 2013 | 07:04 PM
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No backfiring. New power valve from rebuild kit. I have 16 in. of vacuum at idle. Have a 65 power valve in carb now. Wondering if this is to small and if this could make a difference.

No ignition module. Points dist. with MSD box. Was running fine before new carb install.

Last edited by Kim72; Mar 30, 2013 at 07:15 PM.
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Old Mar 30, 2013 | 08:49 PM
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Fixed it!! Stupid me, I had the vacuum lines mixed up. I plugged them all and she ran like a scalded dog!! Sorted the lines out and now all is good to go.

Thanks for all the replies.
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