Racing Fuel Systems

Holley HP 1000 currently have .025 MAB will going larger ( leaner) delay the main circuit ?
Trying to lean the cruise out at 40mph at 2000 rpm in 4 the gear runs rich in the 12’s assume at that rpm im runing on the main circuit

Smaller MAB will likely have the effect you are looking for on low flow.

Agree with rgalajda.

What’s the idle/transition specs?

Ok so .025 smaller / richer MAB will delay mains compared the .028
IFR .035 bottom transistion no restrictor BLP 5300 baseplate not sure what size transition slot

In my experience going .025” to .028” will encourage mains pullover sooner.

A few more questions to work out why rich at 2k.

Is it the annular or downleg 1000 HP?
What size are iab?
Do you know emulsion?

Ok so goung to .025 mab from .028 will delay the mains
I keep getting conflicting answers to that question


Downleg stepped boosters
IAB .067
Emulsion .blp block 51241
028 1 &3 location the rest plugged

Watch these two vids I done a few years ago.

Exactly same carb (850 cfm downleg Might Demon - same venturi and throttle bore diameter as your carb and had same emulsion you have at the time) Exactly the same road going same direction holding same steady speed. Only change was mab. The .025” mab hovered around 1 lambda (for the fuel I use 14.4:1 AFR) https://youtu.be/0FIleHIk-40 and the .028” around .97 lambda (13.96 AFR) https://youtu.be/L1z2gJV5LVc

Tks for that explanation appreciate it
I was going to start with bigger IAB’s

My current idle afr is 13.8-14 but the cruise hoes into 12’s almost immediately
Big cam 260@.050
So basic cruise tuning will be in IAB , jetting as the jets do control how much fuel the transition circuit gets
Do you think my IFR at .035 is part of the rich cruise or not ?