It should be zero it is ported vacuum only there because the vacuum comes from above the throttle blades, so you are good there. Open the throttle blades a little and you should see vacuum. You can easily check your vacuum distributor can by using a mighty vac and apply vacuum to it or just use a piece of vacuum hose to go to full vacuum port on the manifold.
Last edited by sstock; 08/26/2019 7:02 PM.
1953 Chevrolet 3100261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY GalleryVideo of the 261 running1964 GMC 1000305 Big Block V6, sm420, the next cab off restoration
