My 63 with a mild build 68 383 runs almost in the middle of the gauge, like the pic on the left. I do not have a really good radiator in it, something I need to address in the future. The only time I had temp problems with it was cured by timing and a bigger fan. I have a re-curved Chrysler electronic distributor in it and is times for total advance, and not anything radical at that. Pretty sure I have it timed according to Don Dulmage's specs.