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Thi have the floats set to the lowest point on the glass that i can just see the fuel level if that makes sense .



The level at the sight plug is just a good starting point. It's OK to vary the float level if it accomplishes a goal. Back in the day, OEM Holleys had their sight plugs wherever the engineers deemed the "correct" float level for a given application. In your case, I'd try lowering the level below the highest e-bleed...wherever that is. You'll probably need to look inside the carb to be sure. Lowering the float level below the highest e-bleed will delay the start of teh main circuit.

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I have also tried to enlarge the high speed Air Bleed jet before to delay the main circuit but gave up on that because it never helped that much.



I'm not at all surprised. Two things: 1) At very light throttle, there probably isn't enough airflow through the emulsion circuit so that the MAB size becomes a factor. Remember, the MAB is in "series" with the e-bleeds. 2) When the emulsion circuit gains sufficient airflow so as the make the MAB size relavant, a larger MAB can cause the mains start sooner, not later. The greater number of e-bleeds you have, the more likely this scenario becomes.

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this only helped slow speed porpoising when the throttle closed .



I think I know what you mean, but please elaborate.

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In the main block i think it has a total of five ports for emulsion and there are set from the factory like this.
lowest jet/ plug /mid jet/plug/top jet .
I don't remember the size of them though .
The IFR is a 31 i was going to try a 28.
Does this sound correct?



That sounds about right. The e-bleeds are probably .028"? That's a common size in Holleys, and I haven't seen the innards of enough Demons to know if it's also true for them.

The IFR size sounds like it's in the ballpark. Keep in mind that after you reduce the IFR diameter, the idle mixture screws will be out more than the "standard" 1.5 turns. As long as you still have some adjustability, I wouldn't sweat it. The tradeoff is that you will have leaned out the transition circuit.

If I were you, I'd do the following, in this order: 1) do everything possible to maximize idle vacuum. 2) limit fuel to the tranistion circuit through a combination of smaller IFRs and larger IABs. Maybe throw in t-slot restrictors. 3) delay the start of the main circuit (if still necessary).

We can discuss 3 in more detail after you're done with 1 and 2.

Hopefully, your weather is more cooperative for tuning and testing up there than ours has been. Rain, sun, rain, wind, rain, sun, etc.

Jim