The group size only is a reference to the outside dimentions of the battery.
You can use any group size that will fit in your battery compartment.
However, a physically larger battery case is not a guarantee of a more
powerfull battery.

Group 41 Dimentions: 11 13/16 x 6 7/8 x 6 7/8
Group 43 Dimentions: 13 1/8 x 6 7/8x 8 1/16

You can find a chart at:
http://www.rtpnet.org/~teaa/bcigroup.html

Todd
'88 Westy

On Wed, 7 Aug 2002 07:58:13 -0700 Bill N <freeholder@STARBAND.NET> wrote:

I just bought a new battery for my '81 Westy.  I bought a group 41, which was
what I was replacing, but the book at the flaps said the '81 was supposed to
use a group 43.  Anybody heard of using a group 43?  What's the difference?

Bill in the Southwest