I'm running dual Holley 1904s on an Offy intake with Fentons, no heat riser or heat plumbed to the intake, it's only bad on feul when it's cold. Once it warms up theres no problems. I was getting poor milage, but that was caused by an incorrect float setting. I would suggest using the bigger filter housings instead of the little 3" ones, you'll get better flow and more filter area. I used 6" mr. Gasket housings with K&N filter elements.
