[Tommy]

At the risk of telling you things you already know, I'll add this. One common cause of engine overheating is ignition timing that is not sufficiently advanced at idle and under low load (cruising) conditions. On street cars with distributors that issue is addressed by the vacuum advance system. Race engines often do not have vacuum advance because they operate near wide open throttle much of the time. . . If your distributor does not have a vacuum advance, or if the dyno tuning that was done was mostly at wide open throttle for peak horsepower, then your timing may not be optimized for street driving and that may be contributing to your overheat problem. There are procedures for checking your vacuum advance at idle and partial throttle with a timing light.