Thanks guys, Dad was wondering about that since newer trucks have 2 12V batteries in parallel, and those 4 6V batteries added up to 2 12V batteries in parallel.
The guy at FLAPS did show me a 12V batter with 1100 cold cranking amps that is well within my budget, I believe that ~2200 amps would be more than enough to spin over a 12L diesel. Knowing that its a 12V system will make shopping for parts much easier, I had been thinking it was a 24V system for some reason.
