In 1968, these cars didn't have heat soak problems. Our roads and shopping malls were not lined with broken down Pontiacs waiting to cool so they could be started and driven home. The starters were factory fresh and they started without episode on the hottest of days. Of course as new parts, they had proper bearing tolerances, good lubrication, decent contacts and the rotor was not rubbing the stator when it was hot.

There's no reason to redesign the car to correct a worn out part such as the starter when the original design was satisfactory. Repair, rebuild, exchange or buy a new starter and fix the problem at the cause.

This ain't no ford and it doesn't deserve that junk added to the firewall. It's not a clean fix. It doesn't address the cause. It leave two more exposed hot terminals to misplaced wrenches on. And it lengthens the wire.

If you relocate the battery to the trunk because you prefer having the weight back there, you need to remember that the longer cables introduce more resistance. If you double the original cable length, you need to go lower by three wire gauge numbers (larger conductor) just to break even. The negative return is just as important as the positive for this calculation, so count both lengths. You don't want cranking current flowing through the car body and fram because it will also flow through transmission and differential bearings etc. and pit them. The frame is steel anyway, so it's a poor conductor.