83 F150 straight 6 has fire and full but won't start

[Rod-Knox]

How did the plugs look and how did you confirm the spark? The timing gear may have “jumped” but the usual failure of the timing gear is the cam gear strips out and no longer turns. The factory timing gear is some composite that falls apart like saw dust. It usually fails when the engine tries to run in reverse when attempting to start. And the compression should be well in excess of 120 psi.