electrical gremlins

hey just want to say thanks in advance to everyone, im experiencing some electrical problems, car is a 72 duster, with a big block and chrysler electronic ignition, i pulled the motor this spring to deal with some pesky leaks but no electrical problems before and just recently reinstalled it in the car, problem is i have no power, zip nada nothing, i have over 12 volts at the battery, and i have power to my starter relay and starter, so if i jump the terminals on the relay with a screwdriver the motor turns over but will not start as i have no spark, even my headlights will not turn on with the key on or off, i changed the starter relay thinking maybe that could be the issue and to no avail, as well as pulling the starter to make sure terminals were loose and still no power, also made sure block was still grounded to chassis and no problem there, im kinda lost now as i didnt alter anything while pulling or reinstalling the motor, any help would be appreciated as i dont know where to look now thanks FABO!