Best Way to set the idle mix on a 4160

[Gaz64]

Originally Posted by tortuga

One thing i noticed about setting the idle with the secondary stop screw is that if you open the secondaries too much the motor tends to come off the throttle slowly (running on the secondaries?).

On my motor if i set the transition slot square its way too MUCH throttle...Think mine are pretty much covered at idle if i try to balance both ends...My secondaries are tight as frog lips at idle with the primary just cracked. No vacuum leaks, Walker PCV valve set for low vacuum.

One thing with a Holley or other 4160/4150 Holley style carb, QFT AED etc, is to check that the primary to secondary link does not jam in the slot as you open the primaries slowly off idle (engine off). This needs to be checked after final hot idle speed has been set. This is assuming that near equal airflow is occuring around all four throttle blades at idle, especially for 4 corner idle carbs.

Some aftermarket throttle bodies have their transition slots too high up the bore.

Gary