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71 malibu with full interior, around 8 or 9 mpg with a 355 with holley 750 mech secon. 280 magnum cam,world product sportsman heads with 2:05`s built 350 with kit and 3000-3500 stahl,12 bolt with series 4 eaton unit with 3:73`s 295/50/15 tires
 
68 chevelle 454+.60 10.5/1 comp hyd roller cam eddy perf RPM holley 750 Vac sec turbo 350 3000 stall 3.73 gears 275/60/15 getting 14-15 on highway. Wait until I get done with the GV od install!:yes:
 
I get between 8-9.5mpg around town and constantly have my foot in the throttle to "get up to speed".

I am guessing 10+ highway.

454, TH400, 3.36 gears
 
10mpg when I really try to save gas...more like 8mpg on average cruise nights...5mpg when I play a little with it :)
 
396 60 over
11.7 to 1 compression
850 double pumper with no power valves
tarantula single plane intake
262/273 @ .050" solid cam
10" convertor
th350 tranny
3.70 gears
at this point in its combo running 12.20 at 110 mph and was getting solid 11 mpg on the highway turning 3500 rpms plus or minus on 87 octane fuel


396 bored 090 over
10.2 to 1 compression
233/239 @ .050" hyd cam.
rpm intake
3310-2 holley carb
th350 tranny
2.73 gears
ran 13.50 @ 107 plus mph darn close to 18 mpg mix driving in town and highway with some blasts over 130 mph included.
 
Wow, I'm not complaining then! Just got back from a little road trip, I am running:

402, 600Cfm edelbrock, TH-350, 25.7" tires, 3:08s, Electric fan on manual controller.

Before I left, I rejetted and rod'd the carb, went to .095s from .098s, and went down to 73-37 rods from 75-47s, so my cruise was leaner, and my power was richer. 160 miles each way, stuck her at 68mph, and ended up there with spot on half a tank yet! I didn't know what to expect really, but it sipped it pretty miserly!

On the way back, it was a repeat performance, I averaged 17.5mpg:beers:, (not counting my race time!) so I'm MORE than happy with that!

A sidenote: my advance curve in the distributor is whacked right now, I should have left it alone....wish I had known the Mr. Crapsket Advance set was junk...come to think of it, I thought I'd sworn off that stuff years ago, but I must have forgotten. Anywho, all I had to do when I got to the track was fiddle around with the timing (A LOT!!) and ran a 15.7 (no posi, slippery track, 17" tires, handling suspension) at 94mph, so the car was making good power with the carb set that way too! :hurray:
 
I guess my car would be in the middle somewhere. My specs:

454HO
750 cfm edelbrock
HEI ignition
Turbo 400
2,000 stall
2.73 rear gear

14.5 mpg on the highway and 10 in the city if I am trying. When I had my 12 bolt with 3.73 gears it was drinking gas at a alarming rate :yes: so I went to the stock civilized rearend at least for awhile.
 
68 Vette, 427, Erson 235*/.542"/111 LSA large valve ovals 10.5:1, RPM, Eddy 800 or 3310 Holley w/ M-20, 3.36:1, 3400# and a little sleeker than your Chevelles
In excess of 14 mpg last mixed trip
I guess 12-13 mpg normal
 
I get 13-14 MPG in OD with convertor L/U. 60 MPH, 2100 rpm's.
The funny thing is, at 60mph in drive, L/U, approx 2900 rpm's, I still manage approx 12-13 mpg.
Says something about the difference in BSFC at the 2 different engine RPM's
 
My 67 408BB 10.5comp, comp cams .690/.690 lift 280/284 dura super 112/112 super t10 4:11 gears and 31" tall M/T tire got 13-14mpg driving at 55mph and some city driving.
Now I have same motor but voodoo 60212 hyd roller, turbo400 with 2500 stahl converter got about 8 mpg on country roads. haven't done a highway run yet.
 
My ZZ454 gets a reliable 18-19 mpg with a very seldom 20 mpg`s ( only 3 times), thats in fifth gear (.64 overdrive) 3:70 gears, 850 holley dp from AED, and GM ZZ502 cam, 2 1/8 Hooker headers, MSD distributor. The car runs strong and gets better mileage than anything else I own. Gota do something about that dont drive it but once or twice a week and gas $ is killin me.
 
Some of you are in bad need of a wideband and some drill bits.:thumbsup:
Ray if you need a vacation and something to do......I've tried airbleeds and that only got me a bucking bronco. I admit to not being knowlegable enough and not having AF meters.
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