There were no alignment marks made when the distributor was removed from my '49 V-8. What is the proper positioning of the crankshaft for installation? Thank you!

 

MY way, quite probably not the most correct, is to bring the engine around to TDC. Then align the distributor so that the rotor is at no.1 contact. Slide the dist into the hole and allow the gear to engage. The shaft should not be permitted to move much at all. Doing so will disrupt your alignment.
Look at some stock engine pics if you want a visual of the distributor as it appears properly installed.

 

Correct ^^^ except that I'd clarify that the rotor will turn as you drop the dizzy in, and you want it to point to #1 on the cap after it turns. You can't stop it from turning.

The stock setup is that the pointer on the timing cover points to a bump on the crankshaft pulley. If you line those up, and pull the #1 spark plug, you can look inside the cylinder and see if both valves are closed. Another way is to crank the engine with your thumb over the spark plug hole on #1; when it blows your thumb off, it's near TDC.

 

Thank you!