I an looking to replace our starting batter in our boat. The current battery is a group 24 northen something. I installed a interstate group 24 deep cycle battery to run the stereo while sitting. We have the 4.3 volvo carb'd engine. It can be a pain to start at times. I am thinking of going with another interestate deep cycle.
I would stick with an actual cranking battery for the main starting battery. They are better suited over a deep-cycle, for the high, fast loads of a starter. If anything, I would consider stepping up to a group-27 for more CCA's.