timing help

well moved timing and did carb ajustment, samething timing jumping, also checked for crank to rotor play none and disconnected vacuum. using different timing light today.

i didnt read throuigh all the posts but couldnt you be getting a false reading if say your balancer was not fully secured and for whatever reason you didnt have a tight fit between your woodruf key and yoru ballancer causeing the balancer to move around a little bit and give a false reading? maybe check that too? i dunno just a thought