I am quoting this from Mark W- old post...
"This is about as rock simple as it can be. No measurements, no math no special tools, no experience needed. Just line the BB up on the bottom of the timing window instead of the pointer in the middle of the window.
Bottom of the bb at the edge of the window is 12 degrees. Middle of the BB at the edge of the window is 13 degrees. Top of the BB at the edge of the window is 14 degrees."
The only way to make it simpler than this, is to tell you not to worry about timing marks at all... advance the distributor little bit...
if it pings under load back down some... if it doesn't you can advance a little bit more.
It is silly to try for this sort of precision without a dial back timing light anyway. And there is really little point. A degree or two is not going to affect how a stock 3FE runs.
Use premium gas will help with pinging.