Try & find the jetting specs on the Pontiac sprint 6 cyl engine Quadrajet ,,metering rods etc. Should be pretty close to start with.

Quadrajets carbs can work pretty good if you know someone that can work some magic.
Or buy a book on how to tune a quadrajet carb.
http://www.amazon.com/Rebuild-Modify-Rochester-Quadrajet-Carburetors/dp/1932494189

http://www.amazon.com/Rochester-Carburetors-Doug-Roe/dp/0895863014/ref=pd_bxgy_b_img_b

What kind of vehicle you have that weighs 2900 lbs? Early Nova?
MBHD


12 port SDS EFI