Mechanical setup

Factory cars did not overheat when they were new.

Bullshit they didn't.. a lot of the guys that are in the local racing and car scene are 60+ in age. They grew up with these cars and frequently talk about overheating issues.

I've run the bone stock setup on these and with any mods at all the heat can easily become an issue. My bone stock slant 6 never had an issue keeping cool.

Let's also not forget that all of these original parts are now old. Cooling systems, even good ones, break down over time. I've seen cars much newer than ours have issues related to system wear.

Bottom line is, a properly sized radiator, a quality pump, and properly sized and shrouded twin electric fans cannot be beat.