[dataway]

I'm a kid, so I put one stainless block in the driver side, at least allows some heat to reach the intake, warm up takes a couple minutes longer, my experience is the engine is happier sitting at a light with the AC on in 90 degree heat without exhaust flowing under the carb with today's fuels.

My guess is not many people have operational thermostatic valves in their exhaust systems anymore either.

I believe carbs like to be warm, not so sure they like to be roasted. And always seems like open crossovers in warm climates leads to people looking for the best carb insulators they can find. All depends on the driving you do I think.

I think a lot of the things engineers did 50 years ago was based on the fuels available at the time, the physics haven't changed ... but the fuels have.