Just to catalogue everything.
Engine had a loud "tap", from the left side, when I bought "shorty". Pulled valve covers, found #3 exhaust rocker arm very loose, compared to all the others.
Replaced lifter, pushrod, rocker arm, pivot ball and locknut. New intake and valve cover gaskets, equalled, no oil leak, and a smooth running quiet engine.
Two trips to work later, engine starts, runs it's typical quadratoilet choke load up as it cold in the morning.
I turn out of the neighborhood, and loose all power, engine coughing sputtering.
Pull over, crank it, back fire through the carb, which it has not done before. All loaded up badly, can't get 1000 rpms out of it. Backfire through the carb. No power, very little vacuum, as I can feel the vacuum booster go away while holding it running at lights.
Got it home, starts, but loads up quickly, will not rev, dies won't fire up, coughs back through carb.
I think it jumped a tooth, got to go check to verify, by hand turning motor, while watching dizzy turn.
Good times <thumbsdownamilie>