Remove the valve covers and inspect the gaps. Bent valves will fail to completely retract.
Did you attempt to retract the tensioners/guides upon installation? It is not unusual for the new tensioner ratchet to break, resulting in immediate chain slippage. I have experienced it. (and distorted valves)
A leak down test might also be conducted; bent valves and similar issues would be evident in the results.
Are you certain that the motor is not rotating, only with the cams misaligned to the extent that little compression is occurring? Simple verification