I've been having considerable problems since I upgraded my , carb, distributor and intake, I'm in the process of putting on a new Holley 0-8007 390 cfm carb, the on I have is reman and the vendor is taking it back, I've really had a hard time getting the floats to adjust. Before taking the carb off today I put the vacuum gauge on and let the car warm up, the vacuum reading was at 14 to 15.5 and never got higher than 15.5  , I understand 15 to 20 is normal, can anyone guide me on how I need to find what is causing my vacuum problem?