Having modification electrical problems

:banghead: I have a 90 s-10 blazer that due to main bearing troubles have been forced to rplace the 4.3l with a vortec 4.3 with high rise intake and Edlebrock 600 carb. i have figured out the fuel issue but cant get spark from the distibutor. I reset the timing from TDC. and have plugged in the oil sensor. is there other sensor that are required? I have tried three differant distibutors, but due to the differance in the intakes, havent plugged any of the harness other than the alt, and oil sensor. what in the computer is not alowwing the spark to pass the ignition module? there is power going into the distributor:banghead:

Camshaft Position Sensor? or The Crank Shaft Position Sensor? I belive...