Join Date: Mar 2002
Location: San Francisco, CA 94114
I've got a '69 DZ 302 with a 780 Holley. With the current carb settings, it will idle at 950rpm about 3-5 minutes after start up. After I begin driving (another 5-10 minutes), the idle the creep up to about 1,100rpm. It will generally stay around 1,100rpm unless I drive it a long distance. If I drive the car 45 minutes to an hour, the idle will go up to the 1,300rpm range. How do I get the idle to settle down to around 950rpm even after the motor is fully hot without sacrificing start up idle too much? The car doesn't have a choke or exhaust cross-over from the heads.
Here are some details on my combo to help diagnosis: DZ 302 with 11:1 compression, 780 Holley 4053DZ, 247/254 duration @.050, Edelbrock Performer RPM heads, stock intake, 1 3/4 headers, 110 octane race gas.