demonseed was right except that when you feel air pressure on your finger as you are turning the crank damper the engine is coming up on the compression stroke, not exhaust. Which is where you need the number one cylinder to be at TDC with the crank damper on the zero degree mark. As stated, the distributor rotor should be pointing to the number 1 terminal on the cap which on a small block is "approx" 6 oclock as you face the firewall. If the distributor drive gear position hasn't been moved then your new distributor will drop into the slot in the drive gear. You are either right on or 180 degrees off on a small block Mopar. There is no one tooth off with the distributor like a Ford small block can be. You can only be a tooth off if the distributor drive has been moved a tooth one way or the other on the camshaft. I doubt that this would be the case here if all your doing is pulling out your old distributor. Don't use the reluctor in the distributor as a position locator for the rotor. Use the cap as your reference at the number one terminal.
Confused yet??