i changed the radiator in 95 Z28 and put it back together now it will crank but wont turn over. checked the sparkplug wire with screwdriver and got no spark.

 

If the car was working OK before you worked on it, one would assume that you did something to it to keep it from working. A guess would be that some ignition primary wiring got damaged or unplugged. You should retrace your steps and check everything out near where you were "working". Hopefully, you did not soak the Optispark with coolant and killed it.

 

[&:] ditto there pete recheck connections and look around for items that may have been broken or tweeked during your install