from my experience my intake did need to be heated. it was a clifford and i had the same problems. one difference was mine was 292 ci. mine was the older design with no heat provisions. i had a tube welded to the bottom of the intake and ran my heater hose thru it. solved the problem. i only drove my car in the hot humid iowa summers too. p.s. a holley list 8007 is a 390 cfm carb.
