I've recently installed a Proform main body for my Holley 650 double pumper carb. It is now whistling at about 1,000 rpm. As soon as I touch the gas pedal it goes away. I had previously drilled the throttle blades with a .125" drill bit when I was using the stock main body, and have not changed anything and am still using this throttle base. Is this causing my whistle? As well I've noticed that I have no vacum on the metering block port for my vacum advance on my distributor. Does anyone have any experience with this Proform main carb body, and can offer any help?