360 LA engine crank no start

yes, mechanical timing can be 180 degrees of
it is as simple as putting both timing mark at the 12 o'clock position instead of 12 and 6 (facing each other)

How would I know?
put a index wheel on it (to find out if it is retarded or not)

also, the "smaller" valves are the exhaust valves

did you put this together or pay someone to do it?