69 340 problems

You can't time the distributor if it's 180 out because it ain't going to run. You line up the marks with both gears at the 12 oclock position and #1 at TDC. That puts your valves in the correct relationship with the pistons to open and close at the right times.(compression and exhaust stroke). The timing gear has a straight slot in it so you can drop the distributor in pointing at #1 plug wire hole.

(or turn it around and point it at #6, this is wrong) The way he has his timing gears set in the picture he should have dropped his distributor in pointing at the #6 plug wire.

Once you have all that correct then you can button it up and continue to advance or retard the timing off the cover marks and balancer.