3.1 replacement - now it wont start

I am posting for a friend who doesn't have a computer - so bear with me as I try to ask this question correctly...

Original engine was a 3.1 of a 1990 Cutlass - replaced with a 3.1 from a 1991 Grand Prix. The "new engine" worked before the switch-over. Now that it's been put into the car - it won't start. I was told to also mention that the camshaft was already checked.

Does anyone have any idea what to do next?

Thank you!
Anita

Check and make sure everything is properly connected. This sounds like a simple fix like no power to the computer or fuel pump. If it ran before you put it in the new car then look at the electrical connections to the computer and the ignition module.

Does it crank?

He says "yes it cranks", and all the connections have been checked

wonder if there's a wiring pinout difference between 90 and 91? All connectors in their proper locations, seems like I remember there being a possibility of switching a couple connectors in the throttle body 'area' like maybe EGR and TPS or something like that. Could be a headscratcher.....