Before you buy a new distributor, you should determine if the new 350 engine you are installing has a flat tappet or roller cam installed....
Roller cam engines, require a melonised distributor gear be installed on the distributor shaft.
Sure, you can buy any distributor and install a melonised gear, but why not buy the correct unit first up...
So may be a good idea to decide on the engine first, then worry about the incidentials....
IMO, unless I am performing a true back to factory original build, I usually go with a later model Vortec style engine...roller cam, one piece rear main seal, and less wear generally.
Anyhoo....have fun...

