There isn't one. The distributor is synched to zero degrees with a scan tool, it can not be done with a timing light.
Timing CHAIN
setting timing on a f150 4.9 6cyl
Yes.
2.7 has chain, 3.4 (6cyl.) has belt
10 degrees btdc
4cyl. engine does not have timing belt,6cyl timing belt and water pump should be replaced every 100k miles
4cyl chain, 6cyl belt
Computer controlled
The 1990 has a chain. The 1991 has a belt.
If it is a 4cyl then no. It has an upper and lower timing chain. If it is a 6cyl then yes. It has a timing belt, an idler, and a belt tentioner that all should be replaced at the same time.
Timimg marks are on the harmonic balancer and pointer is on the lower timing cover
map sensor 2000 malibu location