I'm trying to get Old Skool back in the water after a brief hiatus. Ordered up a new 2 bl carb and installed however I can't get it to idle down past 900rpm. Idle adjust screw is backed all the way off the linkage. Any ideas? Linkage may be incorrect? The part number was a direct cross from the original. Also trying to install an HEI distributor however there is no vacuum on the old one. Where should I pick up the vacuum? Carb or intake manifold?