BACK THE BUS UP!!!!!If the timing has moved,you could have a valve/pistion interference issue.Push starting it,is a "NOT A GOOD IDEA"on the grandest of scales.
1)Verify TDC
2)Position #1 on the gear.Postion #2 advances the cam and will build more cylinder pressure.
3)After the above,pull all plugs and crank it BY HAND.After verifying everything turns free,measure how much torque it takes to rotate the engine.A good builder should have some numbers on what a correcxtly assembled engine should take to turn over.