Quick 600 holley double pumper tuning tips please???

Hope you've got the 58 cc GT40 heads. Otherwise you're going to loose about 1 full point compression with 64 cc heads. Take the 58's, if that's what they are, and mill them .030 before putting them on. As to the carb, turn the mixture screws in all the way till they bottom, then out 1 full turn each. On the throttle-idle screw ( driver's side of the linkage, turn it out all the way till the linkage stops moving, then in just until it moves the throttle, no more. Too much and you'll expose the transfer slots in the bores ( tiny slots just above the throttle blades) and no matter how you adjust the mixture screws, there will be no effect. Also adjust the gap between the accellerator pump arm and levers till there's no gap, the pump should spit fuel as the throttle moves. Remove all the choke parts, you don't need it. I'm 60 miles west of you and I have no choke on any of my Holleys.

bleedfordblue65 said:

All i really know about the heads is they were off a lightning and they were shaved .040.

D.Hearne let me get this straight... Back out the idle mixtures 1 full turn then leave them alone? Then set the idle screw so that it barely moves the throttle linkage? will I need to change the power valve? What about the jets? Since I am buying the carb used, should I go through it and blow it out or will that hurt anything? Also, when I check the vacuum, What do I hook up the guage to? Will I need an air/fuel guage to get it set perfectly? Will I need to upgrade my fuel pump? electronic or mechanical? Thanks again, the help is really appreciated...

Brett

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What I posted will get you started. You didn't say it was used. If so, bolt it on, start it up and see if and how it runs. Chances are if it's sat any length of time it'll need to be rebuilt, or maybe just the accellerator pump diaphram and power valve replaced. Both are rubber parts and will get dried out and rupture when used.The needle and seat assembly's will probably also need replacing, it doesn't take much trash or corrosion to make em stick open.(or fuel pressure either) Replace the power valve with the same one it had, chances are it's the correct one ( usually a 6.5) I never check the vacuum or air fuel ratio, I just take the time to read the spark plugs. You present fuel pump should be plenty, most are. I fed my 331 sixpack with a low pressure, 30 gal/hr electric. Only time it ran short was when the inline filter ahead of it got plugged with gunk. Jets don't need replacing untill you've got it running long enough to read the plugs, you have to do this after full power runs or driving it hard on the highway. You CANNOT get an accurate reading from running it in the driveway.

Barnes and Noble and other bigger stores will have a book on Holley carbs.

Do you know of any good books to read so I can learn about them?

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Super Tuning and Modifying Holley Carburetors - I highly recommend this one.
It can be found at Amazon.com

Got a 600 DP on my 5.0 kin the Cobra, for the most part runs good. I am battling the car dying on hard stops. Done all the usual stuff, so just tweaking.