HELP Please Idle Problem
 

Can someone help with this. I have a 350 with a XE268 cam kit springs,lifters the whole nine yards from Comp Cams. We put this cam in and broke it in and it runs great,but we are having a problem with the idle when it is in gear. Comp Cams said with this camshaft we could run with the stock converter and 3:42 gears. We put a 2200 stall in it anyway,but are having a hell of a time when putting it in gear and keeping it runing without hitting the gas pedal before it cuts off. any help would be appreciated.
Thanks,
4wheeler

Q jet is your issue here, they don't like choppy idle cams. I do find that additional static timing helps the idle issue, so you could eliminate the vacuum advance and wind in 16 degrees initial timing and try that.

Make sure your advance is staying constant when you drop it in gear. Lots of times the centrifugal is kicking in a bit when you are idling in neutral but when you drop it in gear the RPMs go down, the advance falls back and you get the symptoms you describe.

Easy to check..... with a friend's help, keep a timing light on it while your buddy drops it in gear (foot firmly on the brake, obviously) and watch the timing. If it drops more than a degree or two, this is likely the problem.

This also applies if you are running full manifold vacuum to your distributor's vacuum advance and it's retarding when you drop it in gear (due to manifold vacuum dropping as RPMs go down). However, that cam should have plenty of vacuum to work the vacuum advance even against the load of a stock/near-stock converter.

Agreed, a stock QJet probably will need some mild tweaking to work well with a bigger cam like that, but you should be able to get a reasonably decent idle out of it even as-is. Make sure your idle mixture screws are adjusted for best obtainable idle. Don't be surprised if they want to be 4-5 turns out from lightly seated to give you your best curb idle. Usually, they are too lean in the idle circuits when you put in a hotter-than-stock cam so you end up backing the idle mixture screws way out- and it still wants more.

Lot of us here have used national, you can send them yours or have them send you one first and can adjust as needed so its near bolt n go.

http://www.nationalcarburetors.com/

Thanks, Damon I will give that a try.
4wheeler