Finally found my problem.... I switched my carb for another older 750 cfm holley and it ran great. I think my other carb was leaning out when i stomped the gas pedal, because it would start hesitating. It was a new 750 cfm (80508s) with an electric choke ordered from summit racing. In my attempts to tune it I went from 70 to 72 on the primary main jets, put a 6.5 hg power valve in place of the 5.5 it had in it, and I put the darker yellow spring from the secondary spring kit in place of the black one. I don't have any experience at tuning holleys and I obviously screwed up somewhere. Anybody have any suggestion or thouthts on this.
Holley carb tuning
- Thread starter moparguy
- Start date
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C130 Chief
Mechanical Genius
You may have had a rich stumble, I would think you would have wanted a lower number power valve with that cam. But hey, I'm a Carter and Q-Jet fan.
lead69
hopeless car junkie
Its hard to speculate without knowing what was done to the older carb you put on,also did you disconect the vaccum advance or reroute it in the exchange?.Theres alot of possibilities.
I don't know what was done to the older carb, it came with some parts i bought. I did end up welding up the slots in the distributor and doing away with the vacuum advance, works really good. I did do this prior to switching the carb but still had the same problem until i switched the carbs.... I do live about 2,800 ft above sea level. My guess is maybe i should have leaned it up instead.
C130 Chief
Mechanical Genius
I hope you didn't weld those advance slots very much. With that cam you want about 34-36 all in by 2000 RPM and around 10 degrees static. An adjustable vacuum advance can is a great thing to play with after the mechanical advance is set for max performance.
Welded up approximately 1/8 " . It had 1/2" slots. It is running the best it ever has. If I want to i bought a brand new stock distributor i could put back in. I did do this on an old distributor just in case it didn't work out.. Also replaced the heavy spring with a light one from the MP recurve spring kit. I'm Currently running 16 initial timing. Havn't checked the total, i didn't want to piss off my neighbors to much.... thanks
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