Dear JD;
The valves should be adjusted properly before you do anything else (tune-up wise). Losen each till it clicks then tighten till the clicking stops. Then tighten 1 more turn. This puts the lifter in the middle of It's 'travel'. If the engine stumples when doing this tighten 1/4 turn at a time.
Now the timing. Your dampner may have slipped or the Dist. is in a tooth off.
To set the timing simply retard (vacuum advance off) till the engine stumbles, then advance till smooth. That is TDC. Set & then hook up vacuum line.
Good luck, John M., #3370....
