Ok, so I hope this doesn’t seem like a stupid question. Take away all logical scenarios and just answer in theory. If a timing chain could jump exactly 180’ would the intake and exhaust valves reverse rolls? Meaning cranking the engine would the cylinder fill by pulling air from the exhaust system? And the exhaust exit thru the intake. I have a vortec engine that for all I can say is properly timed. However the distributor faces the #6 plug wire not #1 when I bring engine to TDC. Verified compression stroke by putting finger in plug hole. The truck ran the day before perfectly, next morning would not start. Added fuel into intake thinking possible fuel pump or vats system, it backfired then. Pulled cap and set to tdc, rotor is at 6. I’m lost guys!