I've thought about this common problem several times over the years, and honestly I don't know why I've never had a problem. The only times I ever had an issue with hard hot starts is when I would run too much initial timing. I would just back off the initial and change the curve and total to match and problem gone.
I'm getting some miles on the car right now to work out any bugs in prep for a couple of longer jaunts coming up. You know my engine, 500 hp all iron 427, fresh rebuild, mechanical advance in a cramped Mustang engine bay. It has a marginally good battery at the moment, temps get to 195* cruising slow around town, drops immediately to 180*-185* when back up to speed, NO need for a heater once the headers start cooking the floorboards
. I just now got back from purposely running the car about 30 miles in 90* temperatures and stopped a couple of times for a few minutes to check out some local sights. After sitting for about 5 minutes, the temp climbs to about 210*. Every time it doesn't hesitate to turn over. That's with reproduction battery and starter wires which I think are marginal. I could say that the cam bleeds off some fairly significant compression at start, which it does, but my old cam was much milder and had the same compression, with the same results.
I don't know. It baffles me.
Maybe a heat "shield" would help with the heat saturation and allow it to still get air for cooling, but there usually isn't much room for one.
