depends on what you want to do.
the early one's are easier to retain the efi on. Around 93-94 era.

Anything else, the newer the better. The big changes occured 98 and up, but that is mostly computers and sensors.

They do make a couple of different carb intake's now for the mag.

They also make a bolt on thing to run a mech fuel pump, but you have to run the LA front end.
I prefer the serpentine belt setup.

LA 360 pan and gasket will work on any mag to put it in a car.

if you run a 727 neutral balanced converter, B&m makes a flex plate so you don't need to add weights or anything to make it bolt up and run.