Barracuda No-Start

Hello Folks! I got a baffling ignition electrical issue! I have a 1968 Barracuda that I had to pull the motor to replace the freeze plugs between the engine and transmission. I did some cleaning and painting before I put everything back together. I went to fire it up when I was done, I got no start! I converted it to electronic ignition many years ago. I tested power to all the components, 12+volts to everything, I tested individually the ballast resister, coil, ECU, distributer pick-up. All check out good! I tried replacing all of the components individually including the cap and rotor. Still no-start! I removed the distributer with everything still wired and cap and rotor installed. With the ignition on, I spun the distributer shaft and got spark! I re-installed the distributer and get no spark now! What do the experts here think I got going on?

Thanks in advance!

Are you assuming there is no spark because the engine is not starting or is there actually NO SPARK while the engine is cranking? Have you verified the distributor is turning, by taking the cap off, while you crank the engine?