Dear Senior Member, I am having trouble with my 1979 Chevy 1/2 ton 350 pickup short box won't start shortly after shutdown Not always, but enough to strand me, thought it might be a tooth in the fly wheel missing because it clunks upon turning the key on, again, nothing seems consistent, and sometimes would start after rolling the truck forward. Now it seems the starter, but the starter isn't that old. Could I maybe have a battery too small for my pickup? My mechanic can't find anything wrong with it, the fly wheel is fine. The second time after having it in the garage of shutting it off, it wouldn't start. I'm not apologizing for being a woman but I have much to learn. In a previous post back when, you mentioned "failure of a component at the moment of shutdown"; which component?

Definitely check to see if the battery is sufficient. Parts stores can line you up with a range of your truck's specs and compare your current battery.
Also, have the starting system voltage drop checked to see if it's within normal range. This is best tested while in failure mode, you know...
Heat build-up can cause some funny symptoms.

If it cranks but won’t start consistently, the Ignition Control Module (ICM) may be bad. It’s easy to replace. ICMs are notorious for intermittent starting problems—heat damages them over time. Be sure to apply the heat transfer grease to the bottom of the ICM. ICMs are “electronic points.”