[Roadsters] What's the battery group (size) for a '69 2000?

[D Riedel]

I currently have a 10" L x 6.5" W x 8" H battery in my roadster.  I
could do with a little less height (I can barely get it clamped down).
 What size are we supposed to be running?  Is there a group number?

-- 
Dave Riedel
'69 2000
Victoria, BC