64 Dart 273 Engine Vacuum

17 is good. Valve adjustment will improve vacuum. especially if they are tight from seat wear due to today's fuel with no lead. Without hardened seats and no lead in the fuel to prevent seat wear the valves tighten up. Hydraulic lifters will compensate for that wear . Solids lifters will not and they will tighten up. When you adjust them set them on the loose side. .002 more especially on the exhaust. sometimes a little noisy is better.