I would double check the distributor again, you probably already know that it can be installed 180 degrees out as the timing marks on the balancer will line up on the compression and exhaust stroke, you should be on the compression. Also, when the balancer marks are lined up on the compression stroke, you stab the dist and line up the rotor with the small triangle (should have a 8 stamped in it) in the base of the dist. Here is a post with picks:
http://www.67-72chevytrucks.com/vboa...ighlight=P1345 Also note that your timing is not adjustable on these engines. Moving the distributor around changes the cam timing. Even with the cam timing off a tooth or so the engine will still start, it just may run poorly and set the engine light with a P1345.
If the dist is good, you can check the plugs to see if they have fuel on them to see if you are getting the injectors to fire. You could also use a small spray of starting fluid to see if it starts. If so, your issue would be more than likely fuel related.