new type holley carb center section
 

ive been around holleys all my life but dont know a drrned thing about the new center sections with the 4 things in the front and the 4 things in the back. pretty sure you call them air bleeds. they almost look like the holley jets. what do they do? how do i do anything to them and are they changeable. any and all info will greatly be appreciated thanks chevy art

Well your old Holley has them too, they are pressed in brass that are not replaceable without taking a tap to the main body. Not something to mess with in either case unless you have a clear understanding of what the change will do to the fuel curve. The outer air bleeds are idle air bleeds, they along with the idle jet in the metering block control the idle and transition circuit fuel, as well as the duration of the transition circuit. Since the idle circuit needs less fuel than the transition circuit, you have a mixture screw to adjust that with. The inner air bleeds are for the main circuit, they along with the emulsion bleeds in the metering block control the starting point of the main circuit, how aggressive it starts, and the fuel curve of the main circuit.

carbs
 

thanks mark dont really think i understand what you are saying.. i guess those parts should just be left alone by someone like myself. most of the holleys right out of the box are pretty darn close to b eing on the money. art

The old Holley carbs did a good job when sized correctly for the application with only jet changes. Some of the newer carbs go a little overboard, thinking more has to be better.

Simply, the bleeds correct the fuel curve of the booster. And without any, fuel would tend to siphon fuel even after airflow stopped. Selecting the correct air bleeds and emulsion bleeds allow the correct amount of fuel to be mixed at any airflow through the carb.

carbs
 

thanks again mark. think i understand now after your last explanation. for sure i will never touch them. i am a jet and power valve changer only(i do floats too) art