Unlike a car or potato chip truck, the timing marks can only be seen (easily) from beneath.
The timing light should be connected to #5 or #8 lead. The timing scale is on the right (passenger) side of the front of the engine, and lines up with the mark on the harmonic dampner. If you are a good boy, follow the sticker on the air cleaner.

For bad boys: Stick on a timing tape and time for max advance of 36 degrees. If that pings on hot uphills, back off a little or customize the vacuum or centrifugal advance. Or have your distributor just loose enough to rotate it by hand and set it just shy of pinging as you climb on a hot day.