Brooks my take on all of this is that you are more than likely experiencing a stumble that the carb is doing because of the strong signal the boosters put out, that it is just too rich no matter how much timing you add or how much jet you take away. I've wondered if CSU would make a purpose built carb to use a billet downleg booster up front but the ole reliable standard boosters for the rear just like what The Carb Shop did on that one blow-thru motor that they dynoed a while back. I bet that was to kill some signal but still supply enuff fuel for the whole power range. Another way to find out if it is carb related, which is what I did, was borrowed a friends downleg booster carburetor and BAM, no more stumble or anything like that. It's just a thought.

 

Well.. I may give that a try. What would the permananet fix be though?

 

Not sure if the BRPV that Kevin installs will fix it but here is the article of that one carb from the carburetor shop that uses a custom downleg up front and annualrs in the rear. I bet the downlegs are just for this same reason that "I" had. I am not 100% sure that is your problem but it was for me plus my LM-1 showed way rich at tip in throttle. What does your LM-1 show you when it stumbles?

http://www.mustang50magazine.com/techarticles/m5lp_0606_blown_427_ford_windsor/photo_12.html

 

This is just the opposite though, it's going lean at tip in - it hits 15.5:1 like clock work and pops. The boost guage reads above the carb and it's usually near 2-4 psi.

 

Brooks, Dave changed my air bleeds up on my CSU750. Its probabbly not 'perfect' enough for Dave, but it works pretty damn good for me! He messed with the squirters and a jet change also. It comes up on the transbrake much faster now and for the most part the stumble/bog went away. A little more tuning after I put the intercooler on there and I feel that the throttle response will be nice.

 

Now THAT is way too lean then. Of course you've tried bigger squirters and it didn't help. Smaller low speed/high speed airbleeds may definately help as Bryan mentioned.