I rebuilt the 350 but now can't get it to ...

I think you need to re-time the ignition--remove #1 spark plug (front plug on driver's side), place a ratchet and socket on the crankshaft bolt, stick your finger just into the plug hole, and turn the engine CW through until you feel pressure building in the cylinder. At that point, remove your finger and watch the degree marks come up on the crankshaft pulley or vibration damper as you turn slowly. When the idle firing point aligns, stop turning. Open the distributor so that you can watch either the points just start opening or the reluctor tooth just enters the stator match point while you rotate the distributor body. Tighten the distributor clamp lightly. Check that the rotor is pointing at #1 plug wire. If not, shift the wiring in the cap around until it does while maintaining firing order. The engine should run at that point. Use a timing light to get it right on later. Tighten the distributor when everything is right. Hope this gets you running!