T233 Battery question

[Waterbug]

Both heaters I had burn out were katz. Now have a different brand that is cast aluminum and less wattage but has lasted so far. Only run the heater for an hour or two and then unplug before starting.
As far as batteries go I believe a group 51 is a stock replacement. I did that once then I installed a group 26.
I removed the shock on the hood(never seemed to do anything any way) added a limiting cable to the hood and bent the shock brackets and it fit right in.

I read in another thread that increacing the diameter of the positive battery cable greatly increases the starter's cranking capability.