Remember...there are TWO TDCs, EXH and COMPRESSION.  You need to be at TDC Comp on No. 1.  Then drop the dizzy in so that when it's seated the rotor is pointing at #1.  Then, like BB2 says have the dizzy set bold just loose enough that you can turn the dizzy by hand.  Have the timing light all ready to go, start it and adjust the timing...vac disconnected of course...and lock down the dizzy.  Hook up the Vac.  You're good to go.

BB1
 

Verfiy #1 TDC compression stroke.  I don't trust old factory parts (balancer marks, timing pointers, etc.); there's too much chance something moved or was changed.  The best way to verify TDC is with a piston stop.

After that I set it at 0 and drop in the distributor.  You're going to have to move it no mater where you put it, because as the engine warms up the timing changes.  This will get you reasonably close and it will definitely start. 

The location of the #1 plug wire isn't important.  #1 is the terminal aligned with the rotor when #1 is supposed to fire.  If its advantageous you can make any terminal #1, so long as you follow the firing order and remember that Ford distributors spin counterclockwise.  Some caps are marked #1, others aren't.  If its marked I try to use it for ease of working on the engine in the future.

Ported vs. unported vacuum: I see what makes it idle best and use that.  Ported vacuum provides no advance at idle.  There's no vaccum at the port until the throttle is opened.  Sometimes this seems to help, other times it seems to want the vaccum all the time.  I believe factory they were connected to ported, but there's a lot of reasons for that which have nothing to do with how well the engine runs (emissions, etc.). 

The biggest problem is when the distributor won’t go all the way in the block because the oil pump driveshaft is not in sync with the new distributor.

If you have the old distributor, remove the gear from it and you can use it to turn the pump shaft in ten degree increments until it will drop in.

MS wrote:

The biggest problem is when the distributor won’t go all the way in the block because the oil pump driveshaft is not in sync with the new distributor.

If you have the old distributor, remove the gear from it and you can use it to turn the pump shaft in ten degree increments until it will drop in.

I've found that if you rotate the engine, either manually (socket on the crank bolt), or with the starter, and keep slight downward pressure on the distributor, the oil shaft will line up within a quarter to half of crank rotation.  Works for me.