Hey JW, I too have a 1962 Chevrolet 235ci motor, on my 1948 Truck (btw my Chassis is a '51). Here are a couple pictures. The distributor moves (counter-clockwise) about 1/5th of a turn, under acceleration.
I put a new Vacuum on it that I purchased from Bowtiebits.com (1947-55 Vacuum Advance Part Number: AD-475-MECV-945) and the tubing came from InlineTube.com (part CTV4702) The distributor is an original '48 setup, however, I put a Pertronix 1168LSN6 ignitor into it, which get's rid of the points setup. Still uses a rotor, but it's 2x as better spark I hear. The engine is configured with a 6V setup (6V coil, 6V starter, 6V Battery, a 139 tooth Flywheel and the 6Volt Pertronix Ignitor in the distributor.)
The carburetor is a Carter YF. The Vacuum line that attaches to the Carb, has a straight line with a brass BB that goes over the tube, but inside the nut (like a plumbing fitting). Everything works just fine with the setup. I tested the Vacuum pressure with a gauge that hooks up to the fitting on the outside of your Intake Manifold, just below the Carb. The gauge reads in mercury pressure or inches per Hg. Shop manual says the vacuum should be between 17-21 in/Hg I believe.
