[bonacker]

Today must be Holley carb day! I answered a post on another forum with a similar problem. I'm going to venture on the high revs first. Could be something interfering with the throttle linkage? Are the return springs still on? A slight possibility is the carb mounting nuts are too tight therefore warping the base plate and throttle shaft. As for the secondaries, if nothing changed with the different springs then most likely there is a vacuum leak. All the extra vacuum ports capped off? Again, a warped baseplate could cause leaks. Hope this helps and keep us posted.