Hi List, trying to tune the 350 duel throat Holley that's on our 63 valiant, put a full kit thru it and mounted it , Starts ok but wont sit and idle when its cold ? no matter where i put the choke, yes it is a manual choke modle. Purrs like a kitten once it has warmed up and for a motor thats done 120,000 miles goes like a rocket other wise, any suggestions? RAYCYCLED

Hey, I'm up in QLD working on mine now. My choke is held all the way open and it works good (this is how the carb came) but it does shake and sputter a little till its at running temperature It's not to bad so I just assume this is normal.

Do you have a heat riser from your exhaust to inlet manifold?

Hi I'm in Sydney, No heat riser as yet because ours is fitted with extractors ( headers) I am working on making one , but even at start up it is rough and wont idle and I have not been able to find any clear info on how to tune a 250/350 Holley the little bit on the net is vague, and I thnk it is running rich once it ha warmed up.RAY

Can you tell us more about the engine you have? any mods etc?
Do you know what jets are in the carb?

I used this guide to tune my 350
http://www.junkyardgenius.com/holley/tune01.html

But this is also useful
http://www.chevyhiperformance.com/howto ... index.html

If your spark plugs are brown this can indicate a rich condition (unsure how long it takes).
Be sure to make you have no vacc leaks (though this doesn't seem like the issue).

The 350 carb isn't too hard to tune, the screws on each side (should be two of them) should be turned the same amount. This is all I had to adjust, their are two other adjustments as well one is a screw with a spring and this i believe directly adjusts idle. and their is another sort of plastic 'cam' piece that has three possible places its on the throttle linkage and I belive that also will adjust idle etc.

Hope this is of some help.