An 8V battery is a solution to a nonexistent problem. It requires the voltage regulator to be adjusted to 9.5 volts to keep it charged, which does fry light bulbs (headlights in particular) and it also seriously shortens ignition point life. These are not just idle opinions- - - -I grew up around the best auto electrical shop in Nashville Tennessee in the 1950's when 6V systems were common. The lazy person's fix back then was a special 12V battery with a series-parallel switch built into the top- - - -essentially two 6V batteries that automatically went into series to provide 12V for starting, then went parallel for running and charging. Those things were P.T. Barnum Specials- - - -and the local Nashville battery company (Hester) that sold them found a huge number of suckers to fleece.
If you've got a hot start problem, either your starting/charging system isn't as well-maintained as you think it is, or the engine has some internal problems that cause it to tighten up when it's hot. After 60-something years of doing (and teaching) automotive electrical work, I'd wager I could find, and probably fix the problem in an afternoon. Where are you in Alabama? I'm about 40 miles northeast of Huntsville, close to Fayetteville Tennessee.
Jerry
