Walk Me Through Fine Tuning My set up

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Shane

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Hey again!

Half of me is saying "dont touch anything", the other half is saying "maybe you can tweak a little more HP out of my set up" The car starts and runs great right now..

Its a date coded 70 340, with a purple cam, headmens, and a new(or was new a year ago) 600 DP holley, 4sp tranny.

With the vaccum gage, my idle mixture is set at 1 3/4 turns, and my distributer is set to 36 all in, with 16-18 intial.

My big question/concern is how do I know if my carb is working at peak performance? I took it out of the box and bolted it on.

Do I need to get a fuel to air gage and see the mixture throughout the RPM range, then know if I should start changing jets ??

Just leave it be??

Thanks for any advice..

Shane
 
With the Eddy carb, it says you can clock the engine during WOT and then change the rods and jets and clock it again to see if you can gain any power. But that is Eddy carbs.
Just be sure that you are on a safe road during the WOT sessions.
 
Do you have a 650 double pumper or a 600 vacuum secondary? I'm pretty sure there is not a 600 double pumper.

This is a 600 vacuum secondary:
100_0802.jpg

The thing with the black cover on it near the rear of the carb is the vacuum secondary actuation. There are replaceable springs for it to tune WOT opening, where the metering block takes care of the mixture. Mine has the quick-change cover on it, which is surely worth it if you have one of these carbs.

If you have the double pumper, you will have idle screws back there along with jets that you can tune the mixture with. you may also have a power valve.

My suggestion is to read your plugs. If they are lightly golden brown and have no spotting on them, you're pretty good. As a side note, what is your idle vacuum reading? If its above 13 in Hg, you're probably good with the stock 6.5 PV as well.
 
it is a 600 Double pumper, it runs good , but I keep thinking from time to time that I may have to tune it a bit...

I will have a look at my plugs ..Havent done taht yet, and go from there..

Thanks!

and my vaccum is 13-14...at 750rpm idle.. so I think I am alright there..
 
IMHO, Reading plugs is pointless, unless you consistently use the same brand of fuel from the same fuel barrel.
Pump gas is never of reliable quality and consistency for that type of rudimentary diagnosing.

If it feels like it's pulling well, under load, straight to your engine's estimated redline (based off cam, exhaust, compression ratio and timing baselines), it's most likely within reason.
Surprisingly, I've known of a good many of the smaller Holley carbs to be so very close to correctly jetted, for anything under 375 cubes, that it's scary.

If you want to be as close to 100% accurate as you can, an A/F ratio meter is the thing to have.

If you have a list number of 4776, you have a Holley 600 DP.

Mark.
 
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