How And Why Move Emulsion Jets?

RustyRatRod said
And again there is a "seemingly" modern metering block design and the IFRs are still at the top.

The new stuff is junk. The original Holley's were correctly designed that's why they have 2 emulsion bleeds. I have it from good authority that a properly sized Holley for the engines HP range only requires 2.

The IFR jet at the bottom of the block is immersed in fuel and therefore meters fuel correctly. The IFR at the top will meter fuel and air and will be inconsistent. Where do original Holley's have the jet?

RustyRatRod said
WHY do they use "only" one pair of emulsion jets?

I thinks its just the limitaion of the design. If you look at how Carter does emulsion they use a tube and place the emulsion holes around the tube so as to prevent the air coalescing and causing slugging flow where slugs of air and slugs of fuel leave the booster. The question then is which cylinder gets the fuel and which cylinder gets the air.

You want to limit how much air you use in in the main well to prevent slugging flow. If you watch any Holley slow motion dyno vid you will see a pulsing action coming from the booster. That pulsating flow is a function of emulsion. It does the same thing on a wet flow bench. These myths that emulsion is designed to atomize the fuel is exactly that MYTH!