What's the difference between #3's and #3A's?
I'm boat shopping, and have seen both. I thought I read somewhere that #3A's are stronger - why?
What about parts availilbilty on these drives?
I'm only used to dealing with TRS or Bravo, I understand whats going on in those.
Any educators out there?

IIIA's have larger shafts and are indeed tougher. The IIIA was cobbled together out of the SSM V parts bin. The parts availability on IIIA's is much better, as it is still a current production model. I have an old III, and I haven't had any trouble getting parts I needed, and many of the parts like trim pins you can upgrade to IIIA stuff if you know what you are doing. You can also bolt a IIIA drive leg up to a III bellhousing from everything I've heard, so all isn't lost if you chunk your III.

I had to have a IIIA rebuilt and Mel Riggs didn't have any trouble getting parts. It was real pricey though. But I'd expect that any SSM repair is going to be pricey.

Thanks guys

I recently bought a 3a but had to send it back as my prop
didn't fit due to the larger shaft in the 3a. Finally found
a brand new 3 in the box from lake x mercury for $8500
plus shipping. Only one they had I was real lucky.