Hello CarSnob,
The early engines only had markings on the front pulley zero degrees (OT) and the three degrees before (BTDC). Make sure you have a good set of points adjusted to the correct gap. Which you can check manually, .016 gap. Also you can check with the engine running with a dwell meter, which should read 60 degrees =/- 1 degree.
If you don't have third mark on the pulley which is 25 degrees (BTDC), you will need to set the engine statically. Set the point gap. Rotate the engine manually clockwise till the 3 degree mark aligns with pointer on the chain cover, take note as to which way the dist. rotor is turning also as it reaches the #1 position. The rotor should also align approximately with the notch in the distributor housing. Hook up a 6/12 volt test lamp where the wire connection goes into the distributer and to ground. Just turn on the ignition switch, not starting. Loosen the bolt that holds the dist., rotate the dist. housing slightly away from the way the rotor was approaching the notch. Now as you turn it back towards the #1 position/notch the light will light up. This is where the points are closing at 3 degrees (BTDC). Tighten the dist. bolt.
If you happen to have a 25 degree mark on the pulley you can use a timing light. You should paint the three marks on the pulley with different colors, to distinguish which one is which. Hook up the strobe light, disconnect the vacuum line, if you have one, loosen the dist., and start the engine. Throttle the engine to 2000 rpm, shine the light down at the pulley and pointer, rotate the dist. till the 25 degree mark lines up with the notch, you will need three hands to do all of this. Turn off the engine and tighten the dist. bolt. Start up again and recheck.
If you have a degree wheel you could mark the pulley for the 25 degree mark.
After all this adjust your idle speed.
Hope this helps, good luck, Chris Starcruiser
https://auto.howstuffworks.com/how-to-static-time-engine2.htm