I wanted to get into the whole carb fun deal but...I live in California so, MPG is kinda a big deal. I was just wondering what kinda mileage you were getting with what motors? I'm looking at like maybe 350 or 383. All specifics would help to. Thanks guys...late...

 

I've got an Edelbrock 600 cfm Performer, 350 with stock heads, ~9.5:1 cr, a Weiand Stealth intake, a fairly large cam, and a 3500 rpm stall converter (rear gears unknown), and I seem to get something like 10-12 mpg in the city. When I had the stock torque converter and a Quadrajet, I could get about 19+ on the high way.

Keep in mind that I own a 3500 pound El Camino, not an F-body. Not sure how that would effect things.

 

84 Camaro, 383ci., 5 speed, 3:73 gears, 395hp, Demon 800 carb, 11mpg city.

 

Thanks a lot guys for your replies. If anyone else wants to drop in more info that'd be cool...

 

My pontiac 400 bored .030 over with an 800 cfm Quadrajet, stock heads / intake, street/strip cam, th400 tranny, and 3.73 rear gears gets about 5 - 6 in town and average around 8 on freeway.

 

when my dad had the 302 in a early 60's bel air it got 5mpg on highway he could get to union pier michigan on 1 tank of gas but barely . It had a 570cfm carb, higher comp, 4.10 gears and a turbo 350., and um when stomping on it more of a matter of gallons per mile j/k

 

I have a lifted 87 chevy 4x4 with a 330 HP crate in it. I used the Holley 670 TBI. The truck has 35" tires and 342 gears. I get mid 14's city and mid 16's highway. Oh and it has a 4 speed manual with a 1st gear creeper.

 

My mild 383 blower motor averages about 13 with a home-tweaked Qjet (3 speed auto trans, stock converter, 2.73 rear gears).

I have gotten economy-tuned QJets to spit out a damned-near-astounding 25 MPG on the highway on "economy" 350s in cars with overdrive trannys and tall rear gears.

Big cams, steep gears, and loose converters will drop mileage off in big clumps and chunks. These 3 things are FAR more important to good mileage than what manufacture of carburetor you choose (assuming all are well tuned). Qjets have an advantage in economy over other types of carbs due to the tiny primarys and the fact that they almost all have very lean part throttle calibration (remember they were EMISSIONS carburetors from day one so they didn't usually get set up "conservatively rich" like most aftermarket performance carbs are).

 

Close as mine almost:

Edel EPS
Edel 600 CFM Perf
Edel 350
Pretty radical cam so they say
3.73 from counting the revs

Prob around 13-15 mpg

 

Maybe 5 MPG with a strong tail wind.

 

454 --Edelbrock 800 carb, 10:1, big street/strip hydraulic roller.

TH400, stock stall, 3.73s. I get 8 mpg on the highway and in town I can literally watch the guage go down if I drive very long...wouldn't trade it for the world though!

 

455 Buick 9.5 compression 3000 stall, 4.10 gears portd heads/cam was around 240 degrees with 110 LSA. I was able to pull off about 10 city 13-14 highway. If I babied the gas pedal and I mean babied, I could manage these MPG, flooring it all I could watch the gas gauge go down-its very disturbing. When I installed a 700r4 I gained another 2 or so mpg, made a big difference, but the torque broke it rather quickly,even with a hi performance rebuild
This is why I changed to my current car in the signature, I can pull 25 mpg highway with all the listed mods and the cam is on stock tuning. Although I do miss my big block!

 

1984 Z28

T-56 6 speed
3.42 gears
Comp 274h Cam
Protopline Vortec Heads
Holley 750 double pumper

8-10mpg city, 15-17 mpg hwy (6th gear)

I bought some AFR heads that I started putting on tonight, but didn't finish.. I'll know how it does tomorrow once I get a few miles on it after the head change.

 

I get 20MPG on the high with my 305HO, maybe 12-15 in town.
But I had 2.41's in the rear, yes 2.41 rear gear, found it on the build sheet, and almost cried, just hoped the motor was slugish
very fun on the highway, sucked in town, stoplight to stoplight.
The 3.08's are much better, just haven't paid attenion to the gas gauge. I'm having too much fun with the new gears. I guess around 15 on the highway, and 10-12 in town.

 

1980 Z28, 350, T56, 3.42 rear gears, Qjet, Twisted Wedge heads, ZZ4 roller cam, rolling on 275s at all four corners.

19mpg going to work (call it 50/50 city highway), 23mpg highway. Stuck in city traffic for the entire 300 miles or so I get before fill ups, reduces it to about 16.5-17mpg. I used to get 25mpg highway with the Comp 268H cam. I don't think my Twisted Wedge heads like the big split duration of the ZZ4.
As Damon noted, I am using the lean primary calibration of the Qjet to my advantage. I've boosted the secondary rods a bit to compensate. I get no bucking, surging, none of that, so it works fine for me. No hesitating at the track, either, and years ago, it sniffed within the HC/CO limits, despite no cats. I can't say if that's still true with the ZZ4 cam, though.

These are AC->ON numbers, BTW. I don't drive much without the AC on. It's hot here, ya know.