I've got a 340 with a Holley 750. I was disappointed with the kick when I punched the throttle. I discovered with the help of a bobbie pin that the vacuum secondaries are not opening. I adjusted the throttle cable and gained more petal travel. The difference was amazing but the secondaries are still not opening. I've looked at Holley videos but still not 100% sure the vacuum lines are correct. The PCV valve hooks to the btm rear of the carb? What do I need for vacuum pressure to actuate? Is the 750 too big. Any suggestions are appreciated.