The plot thickens

I have seen real loose oil pump drives and block bushings and the car still run ok. Not perfect but they'll generally run. The timing will usually jump around when you put a light on it but it'll run. I can't imagine the bushing or shaft being so bad it won't run because of it. Are you sure you got it timed right? There are 2 top dead centers. TDC compression stroke (that's when the rotor should point at the #1 spark plug wire terminal on the dist. cap) and TDC exhaust stroke (180* out of time). Sometimes they'll kick like their trying to start if their 180* out of time. Also, run the wires to make sure no wires got switched around. It rotates clockwise and the firing order is 1-8-4-3-6-5-7-2

Voodoo1 just mentioned the ballast resistor and that could be the issue if you wired the HEI to the coil positive wire in the wiring harness. When the ballast resistor is bad the dist. gets power when cranking and will show spark then and the engine will try to start but as soon as it fires you let off the key and the power drops out. Did you try running a direct hot wire from the battery?