Point-type distributor? Single or dual?
Anyway, have you moved the dist drive gear any? Keep in mind the slot at the top of the gear does not have to be in a certain position. But, during normal build it's lined up with the crank, putting the slot in line for an easy range of timing rotation.
Motor needs to be at TDC compression stroke. Correction...at initial timing (10 degrees before TDC). In other words line up your timing mark.
Is your advance working free? Also make sure your dist cap is okay. Including the center carbon button inside the cap.
What ever kind of advance you have...mech, or vacuum, and the #1 plug wire location, the dist should be dropped in place, so you have clearance for rotation to set the timing. Okay. Probably already know most of this.
If you have the motor sitting at 10 degrees BTDC, you basicly want the rotor just coming to the #1 contact inside the cap. It should start, being fairly close in time, unless it's 180 out. Then put a timing light on it, to finish timing it.