jj05
Thanks for the info. My boat is over 40 years old and originally came with a Super Bee Chrysler and might have even originally been a stringer? Who knows how/when the 260A was installed? I'm not sure how to really tell which drive mine actually is - the cover says 250 but I'm thinking my outdrive is a 250 because of what I've gleaned from various sources...
If the propeller spinner is not equipped with the center locking bolt, then it's a 270, or perhaps an older 250.
(the prop shafts were not internally threaded for the locking bolt until the 280/285/275 etc.)
If you have this locking bolt, then it's a later lower unit.
If the transmission oil fill port is located near the 2:00 O'clock position just above the shift mechanism, it may be a 275 or later.
(the earlier 250/270 did not have a fill port here.)
If this is a single screw helmet pin, then it's a 250/270.
If it has the double bolt helmet pin, then it's a 275 or later transmission, of which may not necessarily tell you which lower unit has been installed by someone.