Manifold heat cross over physics and benifits

I'm running an Air-Gap manifold on my 360 in my '70 Duster, it was the only choice with Magnum heads which don't even have a heat crossover. My solution was to get a factory dual-snorkel intake from the early '70s with the vacuum-operated heat riser and fab up some plumbing around one of the header tubes. With that system working I can start up the car cold in below-freezing temps and be on the road in less than 10 minutes.

I actually can't imagine having a heat crossover in summer, even being an Air-Gap manifold the carb gets really hot and boils the gas when creeping in traffic on a hot day (90*+). I need to add a carb spacer but there's no room for it with my stock hood and high-rise manifold.