This photo (from an old article in Rod & Custom magazine) shows the stock timing tab.
In the photo, the timing mark on the balancer is close to 0 degrees; you can see the "0" stamped into the timing tab at the bottom of the widest V notch. The outlined white arrow is pointing at the 6 degree BTDC mark.
Ignore the solid white arrow in the photo; it was just pointing at the timing tab in this magazine article.
You must follow the proper procedure to set the base timing.
The procedure is printed on the emissions control decal that is affixed to the top of the upper radiator cover/shroud.
To set the base timing, the engine must be at operating temperature (thermostat open, stable operating temp), the engine must be operating in closed loop mode and the air cleaner must be installed. The A/C should be turned off.
Block the drive wheels and set the E-brake.
To set the timing, disconnect the 4-wire EST (Electronic Spark Timing) connector from the distributor. Connect the timing light pick-up to #1 spark plug and set the timing as specified (I believe the recommended setting for your engine is 6 degrees BTDC @ 500RPM IN DRIVE...verify this on your Emissions decal)
You adjust the timing by slightly loosening the clamp at the base of the distributor and rotating the distributor to the correct position while the engine is running and you are watching your timing light flash at the timing tab.
ANY movement/rotation of the distributor affects the timing; make your adjustments in very small increments and check the timing light continuously. Shine your timing light directly on to the timing tab and watch the position of the timing mark on the balance relative to the timing marks on the timing tab.After adjusting the distributor to the proper timing, tighten the distributor hold-down clamp, then double-check to verify that the timing is exactly where you want it. Shut off the engine and re-connect the EST connector.