Tonto & Caveman,
I spoke with Jeff @ CMC (Compition Marine Center)
a week or so ago. And It's my understand that the old gear
sets are no longer available as you stated.
How ever now mercury offers a conversion get
that retro's it to make it the same as the 6a's in reference
to the gear that is. The intial retro is about a Grand.
but after that you can exchange gears just like any other
# 6 at normal cost.
Unless it's huge power, you shouldn't have to worry
to much about what I said above. But if it ever came to be
an issue. At least the drives retro now instead of being obsolete.