Rebuilt 318 install problem

OP: PLEASE PAY ATTENTION!!

There have been many suggestions here and it's not clear that you have done any of them

1.....THE TIMING CHAIN may be off. If you read the service manuals, there is a way to estimate this in the service manuals. If you have the camshaft specs you can rig an indicator device on the no1 valves and estimate it that way

2....YOU SEEM TO REFUSE to use a piston stop. THAT IS THE ONLY WAY to determine if the timing marks are correct to the crank with the engine together as it is

3.....I and others have suggested THAT THE DISTRIBUTOR PICKUP wiring may be reversed. Try reversing them and see what happens. This will change the ROTOR PHASING which I already suggested you research

4....."The usual." Are you absolutely sure you have the light connected to the no1 plug? That is the front plug on the driver's side

5....If all else fails, use a vacuum gauge on manifold vacuum, and with vacuum advance disconnected, move the distributor from an purpose retard condition (distributor somewhat CW) rotate the dist. CCW and the vacuum should increase. Reduce idle speed to suit and find the "high vacuum" spot. This will result in the timing being quite advanced, but it should get you close enough that if the marks are right, etc, you should see it with the light

You cannot just stand there and play with it, you have to systematically diagnose it