About to start shopping for a used Bravo outdrive. How can I tell the year of the drive, and can I tell what boat it was originally on? What about if the upper and lower have been swapped? Is the casting #'s like an auto block?

Thanks

One way to tell is to have or post the serial number, Someone here at OSO can look it up for you.

There are certain places on each section of the drive that will help ID a type of drive, But you will need the service manuals to help decode the numbers and where to find the numbers and letters, ect.

For one exmaple see pages 3A-9 thru 3A-16 on this older service manual, Merc now has a few more service manuals out with updated number for over the years.

http://www.boatfix.com/merc/Servmanl/11/11a3r5x.pdf

I hope this helps you out some, Good luck with it.