Hey guys I am trying to set up a rebuilt holley 600 cfm with vac secondaries. Having some troubles. I havnt messed with holleys before but i want to get this one dials nicely. I have a 292 bored .060 with the isky e303 4444 cam. headers with glasspacks and 4 speed amnual trans. Vacuum is pretty low at idle with the cam. also have john mummert aluminum intake, My question is about car set up.
• what power valve?
• what jets and metering blocks?
• squirter size?

Anything else I need to know. I am trying to run manifold vacuum too.

A rule of thumb for the power valve is to use one that is half of your idle vacuum.  That will not necessarily be ideal but it should work well.

The rest is not really something that can be recommended.  You just have to figure it out for yourself.  It will be best to start with the base calibration of the carb, that is however Holley would have provided it, and tune from there.  As with any kind of tuning, change only one thing at a time and take notes as you go along.


Lawrenceville, GA

Might I suggest looking at your dizzy first? by the sounds of it your going to need more initial advance probably around 15 degrees. Do a search on dissy setup or Steve might put up a link. [ I did see your running manifold vacuum]


• what power valve? As Charlie said. I usually set it up looking at cruise vacuum as Im not sure why its suggested by Holley to set it up based on idle when it nothing to do with that circuit. Roughly I find it one higher than the half method. I think you might be right with the 6.5 [standard]
• what jets and metering blocks? Jets. you should be close at 65 ish, but you'll have to play. metering blocks you wont touch.
• squirter size?  again play, with a manual car and if its heavy ..mmm?
secondary spring. I know my auto liked a heavy spring [brown]
Pump cam . try a green one  ; )

Good luck and have fun.




"Came too close to dying to stop living now!"

Thanks you guys. I am not able to get into he carb until tomorrow night. I will post updates for sure. Keep the suggestions coming. One other question. For best performance in my set up .. Holley or Eddy?

Which carb??  Open that can of worms... Still all about tuning.
I went from a 600 Holley to a 450, and now a 600 Eddie , despite lots of tuning there was no real revelations. "I think " The Eddie has a little bit better mid range that's about it..



"Came too close to dying to stop living now!"

Any thoughts on this thing... https://www.quickfueltechnology.com/carburetors/street/slayer-series/slayer-series-carburetor-450cfm-vs.html

One other question. Is there any problems with jetting the secondaries down a bit and leaving the primaries stock ( which is one stage rich for me in Co ). Seems to run better rich.

There is some leeway for the jets you use.  As long as it is not too rich or worse, too lean, it will be fine.



Lawrenceville, GA

As a general rule, concentrate on primary jetting for ‘drive around’ jetting.  Secondary jetting is typically better left alone or made richer to provide a cushion again being too lean under full throttle conditions.  Being at a higher altitude will simply require driving and making adjustments based on those driving tests.  Making changes without driving can have you going a completely opposite direction than what is actually needed.
  
  It’s recommended to first try any carburetor with the factory supplied jetting.  Assuming the manifold vacuum at idle is no lower than 9-10” Hg, then the factory #65 power valve will be adequate.  Some of the Holley 600’s come with a #25 (0.025”) accelerator pump shooter and these do prove to be on the small side when a larger than stock camshaft is involved.  The #31 shooters tend to be a better starting point in these cases but depending upon the camshaft, shooter size could jump to a #37 or larger.  Jetting is best tried with the ‘as supplied’ jets and then go from there.  Leaning the overall fuel mixture by way of jetting does bring on the potential for a dead spot or hesitation which then requires an even larger accelerator pump shooter in which to compensate.  Float levels on both bowls are important on the 4150/4150 Holley carbs and being too high or too low on either fuel bowl can lead to jetting changes that may not be necessary.

Lorena, Texas (South of Waco)

Ted you are the man. thanks for the advice. I found last night that I had a 4.5 power valve in this 600 cfm carb. I think its the cause of my hesitation. I'll be going with a 6.5 to see how it acts. I have around 11-12 inches vacuum at idle.