TedH

I've not been able to achieve an idle below 800rpm since the time I bought my C3 in 1997 (bone stock). My latest improvements that are likely improving engine behavior are a new carb base gasket/plate combo and a blocked off EGR.

When LARS rebuilt my carb, I set the idle mixture screws at 6 turns out from seated and bumped up the idle because it just refused to stay running with the new heads, headers, duals and carb rebuild. Now with better vacuum performance, I not only am seeing a stable 600rpm in gear but it also warms up like a dream (and that's with non-emissions heads, headers and dual exhaust). Lars had me richen it some with a 'step up' on the main jets and primary metering rods after he rebuilt the carb.

I have backed the idle screw all of the way 'off' and both idle mixture screws are at 5 turns from seated (tried 4 turns and the car refused to idle in drive).

It runs like a 'champ' now. Very happy. If I sort out the few bugs left from latest repairs by Friday (trans cooling lines are seeping at fittings), I'm gonna drive it over to NCRS on Saturday in the 'forum caravan (departs Cracker Barrell at exit 10 on I-4 on Saturday at 7am).

:seeya :chevy :hurray:

Lt1er

I'm glad to hear that your getting everything working. But that low rpm idle just means not enough cam to me:) I use a vacuum gauge to really dial in my carbs idle.

TedH

I run the Crane Energizer 272H - 272 advertised duration. 216/216 degrees of duration @ .050", .454/.454" lift at valve (1.5 ratio). Approx 110 degree lobe separation angle.

A good mid-range camshaft that is rated 2000-5000rpm and easily produces 14 inches of vacuum at idle. Emissions legal to boot! :seeya