This is the original Group 24 battery and its box held in placed by a Master Lock Python adjustable cable lock.
On the back brace are the two small "L" shaped brakets that I thought I had to move to fit in a larger box.
Close up of the "L" bracket in the original position.
To insert the larger battery box all I had to do was turn each of the "L" bracket 180 degrees.
Close up of the "L" bracket in the new position
Group 29 battery in its box with cable lock