Measuring is useful, but nothing beats trying something on for size. As noted in an earlier post, my two fibreglass battery boxes were each designed to hold a pair of 4D batteries side-by-side. However, I had decided to replace those 4 batteries with 8 golf carts. For just a little more money, much greater amp-hour capacity, plus a lot less handling weight per unit. However, when I measured the boxes, there was lots of width, but the length was too short by about half an inch in length for 4 GC's end-to-end and side-by-side. After a lot of good suggestions from TWL on how to make new boxes or alter the existing ones, I decided to take a box to the shop when I went to buy the GC's. And, guess what? With some heavy-duty child's play using 65 pound GC's instead of blocks, I discovered that it is, indeed, possible to just fit 4 GC's in an existing box. The trick is to place one pair pointing in the same direction along opposing sides of the case, but offset. That enables the other pair to fit along the either 2 sides, also offset. They form a not-quite-closed rectangle, and wooden spacers will lock them in place. Spatially-challenged, but grateful for all the advice. Cheers, Garrett