cool story! I can picture it!Gees....when I was in Korea way back, the Koreans could make anything work. They put GI 6X6 diesel engines in a 1965 Buick and it ran and drove. In their left over Korean war GI trucks, they would start a fire under the oil pan to heat it up...pretty funny to watch since sometimes things that weren't supposed to, caught fire. Talk about a Chinese fire drill....!!!
I'm guessing the 6 volt batteries had a higher CCA capacity....Hearing that reminded me of something my father told me when I was very young. The sheep station we were living on at the time had 2 Massey Ferguson 65 diesel tractors. One was fitted with a 12V battery and the other one (my dad's) was fitted with 2 6V batteries in series to make 12V. The tractor with 2 6V batteries always started in cold -5 or -6C and was used to tow the other one which just wouldn't start. I guess the 2 batteries simply gave a better starter speed?