All you need is air, fuel and spark... in the right combination of course. If you are getting spark and air, are you sure you are getting fuel? I assume you got the rotor on the right way. I think they are keyed to only go on one way but with the quality of some parts now a days, who know.
If you rotate the crank to line up the timing mark on TDC, your rotor should be pointing at either the front driver side of the engine (almost pointing at the #1 cylinder) or 180* opposite (pass. rear corner). Could be a fuel pump, computer, bad neutral safety switch (have you giggled the shift lever). Does it have the VATS system? Seen those keys go bad or the contacts where they hit be a problem.
Start with the basics.
Also to add: Some of the GM systems require a minimum oil pressure to allow the computer to start the engine. A bad oil pressure sensor or even pulling the wire off the sensor can cause a no start problem. They typically turn off the fuel pump, so you'll see spark but no fuel. Make sure when you routed the wires, you didn't get anything disconnected.