I'm using a 2002 bottom end to upgrade my 86 engine.  

1) the 86 engine will get the extending cam chain tensioner
2) the 86 will get the clean polshed right side clutch cover.
3) the 86 will get the clean polished left side alt. cover.
4) the 86 will get the 2002 starter gear to relieve back kick shock.
5) the 86 with get the clean low mileage starter motor

Questions:

On item 2; and issues or is it a straight bolt on?
On item 3; can the 2002 stator stay on the cover? or should I swap the 86 stator onto the cover.  are the stators the same?
On item 4; when installing the shock gear, does the starter idler gear need to get changed too?
On item 5:  are the starter identical?

Thanks!!!!!!!!!!!!!   Mike in NJ
On item 4;

The alternator stator should be the same, but I am not 100% sure, regarding pickup coil positíon.
You have to swap the alternator rotor! Timing is different on '86 and 2002. When you swap the rotor, the stator is quite easy to change. 6 screws at least and be done with it. Alternatively you had to swap the ignition box, too, and mess with the wiring.

Shock gear (friction clutch) and idle gears are paired. The shock gear is a bit broader than the old version, so the idler is broader, too.

Also the big pinion on the 2002 clutch is broader, according to the smaller friction clutch pinion. As verslagen mentioned, check alignment. Some things reveal as obvious. And mention the thrust-washers!