3.4, and 3.8.
The 194 3.1 only
GM L82 3.1L V6
Yes
yes it will fit
No, they are 2 totally different bodystyles
No, the compressors and mounting points are different on the 95 Lumina
Yes
No, there is no information suggests that a 1996 Buick Century 231 will fit into a 1999 Chevy Lumina.
If they are both 3100 engines...yes. Direct swap. The only thing you MAY have to change would be the motor mounts.
No, Chevy Lumina Z34 ever came with a 3.7L engine. So probably not.....
Yes it will, I did the interchange on mine
The 99 Buick Century 231 engine will fit into a 96 Chevy lumina with a little fabrication.