worst case it can always be helicoiled
Imagine the alternator is actually someone you are chatting up in a bar in Thailand.The correct size bolt(or girl) will slip in easily and tighten up nicely and will leave you feeling good with yourself.The wrong size bolt(may not actually be a girl!) may start off feeling correct, but soon you will feel that something is not quite right and everything is too tight and somehow it not the correct fitment.This leaves you with two choices...1:You can back off before its too late, make your apologies and call it a day and leave the job to someone else.2:Blindly keep going and really get yourself in a mess, OH! but by then its too late and everything is crossthreaded and cockled.Yes you may feel less of a man, and yes you may feel the need to scrub yourself clean and pray no one finds out what you have done, but we wont think any less of you.
exact length or finish in your half ass description....
passivated.....?