I had a slow crank hot situation on a 496 with a Denso starter. Battery in trunk originally using the car chassis as the ground/negative cable. Adding a dedicated 1 gauge ground wire from battery to block helped a lot.

Heat does slow the minis down but as many have said, with heavy cables and a good battery they usually get it done.

One option for the cables is to make your own. NAPA has all the stuff... heavy wire, ends, heat shrink. I crimp the connections as best I can, heat with a propane torch then feed in rosin core solder until the crimp is full. When cool, slip the heat shrink over the connection and warm it up. Done, neat looking and functional.