The engine was running ok.
I was going to replace the smog pump and had everything pulled but couldn't get the old one out, so I put everything back on the engine.

Now it will not start, the timing light is flashing on the plug wires so ignition seems ok. It doesn't even pop.

What is the next troubleshooting step?
I'm thinking fuel delivery, it has 1/4 tank of fuel.

 

the most likely problem is something you left unplugged without realizing it. check the plug into every sensor anywhere close to anything you might have touched. this is by far the most likely type of problem.
if you don't find a problem, spray a moderate amount of starting fluid into the intake and try starting again. if it starts for a second and dies, you would appear have a fuel problem, though it still could be a bad sensor not allowing things to work right.
if you have access to an OBD1 diagnostic scanner, it may be helpful in diagnosing a sensor thats not connected

 

Listen for the fuel pumps when you turn the key..I had a similar problem in that I broke a wire after rebuilding the PS box. look to the obvious first, anywhere that you were working.