My engine (410) is in an A100 van under a doghouse cover. I initially ran a mildly ported Weiand Action+ with exhaust crossover blocked and a Street Demon with composite body. No insulator under carb, all fuel line covered with Fire Sleeve. No boiling or vapor lock. Then installed the 750DP on that intake with the insulator shown in previous post. Still no boiling or vapor lock, or any hard starting. Installed the Air Gap with the insulator and the DP, no change. All I can safely say is the AG as designed can make some difference with heat soak and related symptoms, how much? No idea. I just did all I could to protect all else from heat as best possible. The AG improved things performance wise obviously.