Oh dear!
Big mistake
. The NEW 1600 ring gear I have in my hand has a definate angled rake cut into the teeth from the "correct starter drive gear" side
. To flip the ring gear over, the teeth are square, so the starter pinion won't be pushed back on start up
. I do believe you will shortly trash your starter
. Ask your mechanic friend to re evaluate the ring gear philosophy
. sorry for the bad news.
Gordon Raymond
Big mistake