This old BF M-M that I brought home last week needs a battery, I borrowed one when I cranked it up to drive on to my trailer and to unload it from the guy I bought it from, his battery was too large to fit in the tray and I just strapped it down to make do temporarily. I took a measurement of the battery tray this evening and its 6" x 9", rather small, tractor has 12 volt alternator as it was swapped over many years ago. Reckon I'm going to take some angle iron and build a larger battery tray, probably about 8" x 12" or 8" x 10" to accommodate a larger battery, I don't know of any small batteries that would sit in the current tray unless it was along the lines of a lawnmower battery and I'm sure there probably isn't enough cranking amps in one of those. I'm going to measure some of my Ford tractor batteries this weekend to see exactly what dimensions are needed to build a new tray unless some of you can point me in the direction of a little battery that will fit...