>Many tuner books recommend drilling out slightly, the idle bleeds on the Holley 3310 to lean out the idle....idle being too rich with this carb on a 350. Has anybody done this? Does it work? Obviously I want to know before I mess up my carb! I've dropped my primary jets to 70's and have my mixture screws out 1/2 turn only.....and it still smells rich. FP is 6psi and my cam is a ZZ4. Everything else runs great! When the sec. kicks in, the car just takes off with no bogs!

 

I haven't drilled out fixed orfi, but I have messed with replaceable bleeds. It doesn't take much, and making them bigger is a lot easier than making them smaller. You need precision drill bits, which last time I checked were about $100 for a set that would cover both idle and high speed sizes.

 

>So, using the interchangeable bleeds: do you need large changes to lean out the idle mixture?