This is a very long thread so I didn't go through all six pages to see if anyone mentioned this. Sacramento area summers are hot and getting hotter (I think we had forty-five 100 degree days this year). I've been running the open Moroso phenolic (plywood really) spacer under the Q-jet on top of the iron manifold for about 25 years now after I'd noticed how the engine wood (pardon the pun) misbehave on hot days. It's been magical. That spacer is about 3/8th inch thick; thin enough that all carb hookups are nominally unaffected save for the divorced choke rod needing a minor up-bend. Way less heat related fuel issues.
