Have a look here:
http://www.4secondsflat.com/Fuel_Delivery.html
Click on the image for a full size pic.
This spacer and 2-3/16 gaskets will give you a total of about 7/8" of 4 hole spacer. The Aramid fiber gaskets have superior heat insulating property's.
They are cut to Demon 650 - 750 venturi bore spec 1 11/16" for a perfect fit and no air flow disruption. Using a spacer with the wrong size holes and not centered to the venturi's is a giant step in reverse.
I'll offer them as a kit to Club Cobra Members for $65.00, we also have the correct stud kit for $7.95.