99 yukon 5.7 vortec motor put in a 96 chevy 1500

[fly-esr]

I put a 5.7 vortec out of a 99 gmc yukon in a 96 chevy 1500
i am having trouble getting it to start
for some reason the spark isn't getting to the plugs
i was told the security ignition on the yukon is not in the 96 and would keep it from getting the spark
i am not sure if this is true or if so if i can by pass the security setting
i have the computer and wiring out of the 99 yukon in the 96 chevy 1500
any help would be appreciated
thanks