I have a feeling my car is getting way worse mileage than it could be. Whenever i tell someone that, they always respond with "Of course its that bad on gas its a big block chevy!" but i think it might be a bit worse than it could be. im getting about 11mpg. Im thinking the culprit is the 770 steet avenger sitting ontop of my motor. Would switching to say a 650 cfm edelbrock make my economy go up, or a qjet? and if i were to switch to a qjet, whats involved in that procedure?

1 more thing: would downgrading to say 3.42 rear gears from 3.73's make my economy better, without hurting the performance TOO much?

Thanks.

 

700r4 trans? if so go for 3.42's on the street....as for the carb, if u can lean the mixture at all do it....if not a smaller carb SHOULD effect MPG in a possitive manner, but may not....has it had a full tune-up recently

 

My dads almost stock 428 in his 68 firebird used to get 6mpg with a th350 and 4.10s i think.

 

oh dear god, thats horrible, mind you those gears r huge, n he prolly has some gnarly holley on it. Holley isn't known for fuel economy, just dumping gas into the engine in a nice manner

 

If your getting 11mpg then it gives me hopes for my 350

 

Im thinking if i get an electric fan, an edelbrock 560 cfm vacuum secondary carb, and 3.42 rear gears, i might be able to bring my MPG numbers up to 13-14. this is my daily driver, n yeah its hurtin the ol' wallet, but i love it to pieces.

 

summitracing.com, p/n JET-36002, 800 CFM q-jet.

Putting a 560 CFM anything on that 461 would pretty much be a criminal act. The q-jet above will give you the economy you're looking for, and the power on tap when "required".

 

nice call five7

 

oh thanks man, right now with my holley, do i have to switch anything major to put a q-jet on my motor? im getting a new intake, cause mines a flat-as-a-pancake stock one?

 

Just get a spreadbore intake.

 

id either go with the Qjet he mentioned, or just switch it all to EFI.... really, if it was me, there wouldnt be any question, id switch it to EFI, and run a lean cruise mode as much as possible with a eye on the exhaust temps.

 

i WOULD switch to EFI, but number 1: TBI seems foregin to me and gets lots of cut-downs, number 2: i dont have a billion dollars for a TPI-style EFI unit, like the ram jet or whatever. i think im gonna go medievil style and stick another carb on it. I like the sound the carb gives the exhaust too

 

both TBI and TPI suck for performance applications.
i would run something that looks alot like a standard single plane intake, with a elbow and a throttlebody on it.... cheap in comparison to the other EFI intakes too.