10-19-2016, 01:19 PM
An 8D is 20.75 x 11 x 11 inches. A 31 Group battery is 12.9 x 6.75 x 9.27 so they are too wide to fit 2 side by side and to long to fit 2 lengthwise. I guess you could fit 1 Group 31 at a 90 degree angle to the other one and get 2 Group 31's in the space of a single 8D.