how many Quadra jet racers adjust the internal lean limit screws

just curious.. how many racers who run Quadra Jets.. adjust the primary lean limit setting that is under the plug shown in this picture..

http://www.circletrack.com/techarticles/ctrp_0607_quadrajet_tech/photo_06.html

earlier models have the screw buried in the base plate..  

this might really improve power levels. and off idle flat and fat spots..

it limits how far down the primary metering rod hanger can drop..   this effects primary air fuel ratio...

since quadra jets have small primaries..   this really effects how the engine runs just above idle...


on a stock engine carb rebuild.. this double D topped limit screw should not be touched..  as there is no set height.. it is a tuning adjustment..  different calibrations have it at different heights..


there are a bunch of Q jet articles on the various magazines on this site.. none of them really cover this adjustment ...

i don't think i would make more than a quarter turn at a time to find the sweet spot.. seat of the pants..  using an air fuel ratio gauge with the secondaries blocked out..  

this might really make a huge difference in how your quadra jet runs..   i know it does on street motors...


since the primary rod holder is held down by vacuum..  and only pops up when you get on the throttle and reduce manifold vacuum.. this limits how lean your engine can go on the primaries..  

i have an idea.. that most  check for secondary operation and wide open throttle power levels when the secondaries are open..  

 well you get the idea..


there is little instruction on this adjustment..  as in the rochester manuals.. if you change the adjustment.. they say to replace the carb bowl..    this is a factory adjustment only.. but we all know.. that anything to make more power.. and can be turned .. is going to get messed with.. if you understand how it works...