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Old 05-17-2007, 11:13 PM
451Mopar 451Mopar is offline
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Question More Holley tuning questions?

I got the 360 in my RamCharger running, and I am running the Holley truck avenger carb. The carb has a stumble off idle that I've been messing with.
Making the accelerator pump/jetting richer helps with the problem, but now the plugs are reading really rich with 70 jets and 0.035" nozzel, and black pump cam. I sort of disabled the secondaries for now, just so I can concentrate on the primary side. I installed two black springs and two brown springs (4 total) into the vacuum secondary to keep it from opening.

Just a while ago I re-jetted the primaries to 66 jets and drilled the 0.035" accelerator pump nozzle to 0.041". It seems to be better, but I noticed my idle vacuum is lower than I thought , about 9"-10" with no load, and about 6"-7" idleing in gear? I need to re-check with a different vacuum gauge because the engine does not idle rough, and I have no problem with my vacuum brakes.
Anyhow, if the vacuum gauge is correct should I install a 4.5" or 3.5" power valve? I forgot the formula on how to pick a power valve value.
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Old 05-17-2007, 11:20 PM
beepbeepsrule beepbeepsrule is offline
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You definitely need one lower than 6.5 imo.....
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Old 05-17-2007, 11:26 PM
beepbeepsrule beepbeepsrule is offline
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I forgot to give advice on which one. I can't remember the recommended percentage, but if that vacuum reading is correct then go with the 4.5
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Old 05-18-2007, 12:22 AM
451Mopar 451Mopar is offline
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Thanks, I was thinking of using the 4.5" PV, I have extras of the 4.5" and 3.5"
so it's not like I have to buy it anyhow. Just need to mess with draining the fuel bowl and removing the metering block (again!)

Anyone want to swap a Holley quick-change rear fuel bowl for a double pumper carb (from my old 850 cfm DP, before I went to the 1,000 cfm vac sec carb) for a front quick-change bowl?
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Old 05-18-2007, 08:37 PM
crisser crisser is offline
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Try the 4.5 PV with a 31 squirter and the pink cam.
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Old 05-18-2007, 11:13 PM
451Mopar 451Mopar is offline
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Well, I'm glad I checked my vacuum gauge! I hooked my miti-vac up to the vacuum gauge and found my vacuum gauge reading is about 50% low!
When my vacuum gauge reads 10" it's actually 15"!

Anyhow, I think I will hold off on replacing the power valve untill I get a new vacuum gauge.
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Old 05-19-2007, 06:16 AM
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ttraut@unlockit ttraut@unlockit is offline
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Quote:
Originally Posted by 451Mopar View Post
I forgot the formula on how to pick a power valve value.
Holley recommends take the vacuum at idle (under load for automatics, they didn't say to put a load on manual transmissions) and divide by two. 11 Hg = 5.5 powervalve. If the number is even (say 5.0), go to the next lowest powervalve (in this case 4.5).

Terry
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