I had him tell me where exactly the exhaust fully closed and the intake just started opening. I looked at the timing mark and the piston was exactly at the top.
This statement doesn't sound right unless you are generalizing.... ^^^^^
The exhaust does not fully close before the intake starts opening...
The intake starts opening before the exhaust closes, that is what they call overlap - how many degrees the intake valve and exhaust valve are open at the same time...