There is a pointer bolted to the front cover at about the 11 o'clock position viewed from ahead of the engine. There are timing marks etched into the largest diameter of the crank pulley. The main segment reads from about 30 BTDC to 30 ATDC. It's easier to see the crank pulley marks from below. Paint a white stripe on the TDC mark to make it easier to see contrasting pointer.

Sixto
87 300D