Power valve first or jetting?

[Ghoste]

When carb tuning which should be done first or does it even matter?

[el dub]

What, no mechanics on this site. If I was going to tune my carb I would buy a rebuild kit and a spring kit. The rebuild kit comes with a power valve in it. At least in my application, a Holly 3310. That eliminates that. Plus, when you buy a carb, and you tell the speed shop what it is for, it should be pretty close to having the right jets. But I really dont know the answere cuz I dont know what carb you have. Have fun.

[Ghoste]

Not a carb tuneup but tuning one for performance at the track.  The reason for the question has more to do with how one system interacts with another than anything else.

[doctor4766]

I would think, since the power valve is chosen according to your engine vacuum anyway, it shouldn't matter what order you do them in Ghoste. That is of course assuming changing the jets isn't going to affect your vacuum.

[b5blue]

  I agree, power valve is set by vacuum so it could be a back and forth thing as everything is dialed in. Unless your off by a mile on the carb. ignition is absolutely first before carb. tuning then idle settings to get that first "good" vacuum reading. (That may send you back to vacuum advance settings adjustment if used.) Then figure power valve rating off that, testing for jets and accelerator pump back and forth....what FUN!!! 

[maxwellwedge]

  I agree, power valve is set by vacuum so it could be a back and forth thing as everything is dialed in. Unless your off by a mile on the carb. ignition is absolutely first before carb. tuning then idle settings to get that first "good" vacuum reading. (That may send you back to vacuum advance settings adjustment if used.) Then figure power valve rating off that, testing for jets and accelerator pump back and forth....what FUN!!! 

[firefighter3931]

Ignition first ; then powervalve based on vacuum and finally jetting. 



Ron

[Musicman]

Ignition, Idle circuit, power valve, jetting... repeat as neccessary 

[Budnicks]

If it's going to be for track use eliminate & block off the power valve & jet up a couple of sizes you don't need it at the track, it's for driveablity & quality of idle...