I would start by making sure the distributor is in correctly. Sorry if this is too basic...
Set the engine so #1 is at TDC on the compression stroke. To do that, pull out the #1 plug, put your thumb over the plug hole, and have a friend slowly turn the motor over (one click at a time, using the starter). When you feel the pressure in the cylinder try to blow your thumb out of the hole, you're close. Then look at the harmonic balancer, and line the mark up with the 10 degree mark on the timing cover. Take off the distributor cap, and the rotor should be pointing right about at the #1 post. If it's not, remove the distributor and re-install it with the rotor pointing at the #1 post. Try to make sure the distributor is in the middle of the "rotational range", so you can turn it one way or the other to get the timing perfect.
Note I said above to have the timing mark lined up with the 10 on the timing cover. That's because initial base timing should be 10 degrees. You could line it up with 0 if you wanted, you should have enough play in the distributor to get the timing right.
Also, double check to make sure your firing order is correct. Remember the rotor turns counter-clockwise, and the cylinders are numbered 1-4 front to back on the passenger side, 5-8 front to back on the drivers side. It's not a chevy!
I suppose it's possible the module on the distributor is bad. If you have a spare one around, you could replace that too.
Good luck!
Jeff