[cleanspeed1]

Forced induction with bad tuning = low mpg. There are plenty of cars here that are getting high mpg with boost ( I have been trying to find the DSM turbo Eclipse/Laser clone that has been in the 40s and he races it ), and STS is getting high mpg with their rear mount turbos. The EFI let's you take liberties with tuning that the carbs won't.

The HVAC question: with all the advances that have been made, you can have the A/C and it not be a penalty; just go big on everything including the blower motor. With the temps and humidity in LA, ya just gotta do it. Look on Vintage Air's website for ideas, and raid a late model Camry or Lexus.