I'm attempting to create a fast, cool car with a Chevy Small Block (350ci) and have thought about adding a blower. Mine is mostly stock save a mild hydraulic cam for more low end torque. What was the gas mileage on the blown small block in the June 2006 issue and what can I expect with mine?  

well, you dont get gas milage from an engine dyno, but rather by the combination of the drive train you use. what kind of car are you going to put it in? say if you put it in a 69 camaro, with 3.55 gears, and a t-350 tranny.. id say you could get 12-14 mpg if tuned right and didnt get on it too much. swap in a 700r4 or 200r4..16-18 if not a little more, and a little more if an 5 or 6 speed manual with o/d is installed. also varys on tire size and width. expect less with a bigger car.  

Its going in 73 Pontiac Ventura... Like I said im sure everything is stock, probably right down to the rear end. And the tranny is a basic 350 model.  

well, that just a nova with a different name right? so im taking it has 3.08 gears in it. Im running the same drive-train, though with a shift kit. so i bet you could knock down 16 mpg in that car. i get 13 with my 454 when in cruising the highway. but i strongly suggest the shift kit.  

Personally I would go with a different blower setup if MPG is a worry. Roots blower are heavy, ineffecent, and suck thru which all effect MPG. Suck thru is the biggest issue for Fuel mileage since you can't install a bypass or blowoff valve to allow the blower to "free-wheel" and its constantly trying making boost and robbing crank power even when your just crusing down the highway. With a Vortech/procharger style setup or any blow thru setup you can run a bypass/blowoff valve and relieve ALL the air pressure (both negative and possitive) under crusing conditions. I've setup a few vortechs now on EFI cars and lost less than 1mpg on eash setup IF I stay out of the loud pedal.  Although I did like the cheap 350 mini roots in this magaine, great setup on the cheap.  

You said you have installed the on EFI vehicles, but what about a carbuerator(sorry if it is spelled wrong). I'm planning on using a 650 holley vacuum pump. And what is a vortec blower? I am relativly new at this and don't have a lot of extra cash.