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Username Post: Mileage        (Topic#189015)
Senior Member
Posts: 513
Loc: San Jose, CA, USA
Reg: 06-21-00
05-07-08 09:11 AM - Post#1428007    

Hi, I finally had the opportunity to take a 400 mile round trip cruise cruise in my '57 HT since transmission upgrade. It's a more/less stock 283 with original WCFB carb, HEI, 200-4R transmission, 3.36 rear, stock wheels and tires. Freeway mileage was about 19 mpg. Does this seem low? I was expecting in the low 20s. I'm thinking of swapping the intake and carb for 570 or 600 cfm.



greg pharr 
Posts: 891
greg pharr
Loc: North Mississippi
Reg: 07-09-03
05-07-08 09:23 AM - Post#1428014    
    In response to RSB

Sounds like you have a pretty good combo. I have found it pretty challenging to get much more than 20-21 mpg on a carburator. Most that go over 20-21 mpg are fuel injected. Every now and then, you will see an exception, but not to often in my experience.

57 2 dr Sedan driver

Valued Contributor
Posts: 2971
Loc: Cameron, Wi, USA
Reg: 11-09-01
05-07-08 09:25 AM - Post#1428015    
    In response to RSB

I get about 18-19 with a 327 power pack heads, 500cfm afb carb, 700r4 with 3.55 rear and 235-75-r15 tires.

57 Bel Air 2dr Ht
327 700r4

Edited by 57tim on 05-07-08 09:26 AM. Reason for edit: No reason given.

Senior Member
Posts: 9224
Loc: So Cal
Reg: 04-14-04
05-07-08 09:39 AM - Post#1428025    
    In response to 57tim

Sounds pretty good to me...


"10th Year" Silver Supporting Member
Posts: 2587
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05-07-08 09:47 AM - Post#1428030    
    In response to RSB

ZZ1 350, 345hp, Eldy 600 cfm, 200 4R, 3:55 rear. Gets 20-21 on highway, 13-17 around town depending on how I drive it.


'55 210, GMPP ZZ3, 200 4R, 12 bolt 3.73 posi, CPP P/S, ABS P/DB.

Nothing is foolproof to a sufficiently talented fool

Deceased Member
Posts: 11178
Age: 78
Loc: Rolling Hills, Ca,
Reg: 12-30-01
05-07-08 03:46 PM - Post#1428244    
    In response to tri5ss

I usually don't do much distance traveling in my 55. It has a 5 speed and a 4.56 rear with a supercharged 350, and I get about 11 MPG around town, and maybe 14 on freeway outings...But it is quick !!!!


Honored Member
Posts: 27138
Loc: Katy, Tx, USA
Reg: 07-06-00
05-07-08 04:00 PM - Post#1428258    
    In response to RSB

I think you are getting great mileage with your combo. As Greg said, 19-20 is very good with a carb.

I have a 67 Nova with a 350 (mild cam), 200-4R, and 3.36 axle - it gets 17 mpg tops.

I think anything over 20 mpg real non-exaggerated mileage is difficult even with EFI. You'll have to baby it big time to get that even with the best combination.

Senior Member
Posts: 2021
Loc: Ohio USA
Reg: 08-02-00
05-07-08 06:32 PM - Post#1428376    
    In response to Rick_L

RSB does your car lug with the 336 and overdrive with the 283? A good number of folks have suggested not going under a 355 with a 283 and overdrive. But seems gas mileage would better.

John H.
55 BA 2dr Sed owned since 1979, sold 6/1/09;
1957 Conv (starting to restore)

Honored Member
Posts: 27138
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05-07-08 06:38 PM - Post#1428382    
    In response to C57Heaven

My 350 Nova with the gearing mentioned lugs pretty badly below 25-30 mph, but is fine otherwise. A 283 with a stock cam is probably the same or a bit worse. It's going to be very dependent on the carb and tuneup on just about anything. I just put the shifter in D rather than OD if I'm doing below 30 mph for any distance. It's also a good idea to use a vacuum switch on the lockup.

Senior Member
Posts: 513
Loc: San Jose, CA, USA
Reg: 06-21-00
05-07-08 07:34 PM - Post#1428451    
    In response to C57Heaven

  • C57Heaven Said:
RSB does your car lug with the 336 and overdrive with the 283? A good number of folks have suggested not going under a 355 with a 283 and overdrive. But seems gas mileage would better.

First let me say thanks for all the replies. I guess 19 mpg isn't too bad after all. I generally drive the car in "Drive" around town and shift into "Overdrive" for the freeway. (Converter lockup at 25-30mph is a real drag and the vacuum switch trick doesn't work on a WCFB.) On the freeway, the car will hold its own just fine but doesn't accelerate well without downshifting. I have an old 57-64? 'P'osi unit with 3.70 gears I have been wanting to try but it needs work. I wonder how much mileage I would lose?

Edit: All I know about the camshaft is the engine rebuilder used an Elgin E923 cam with .420/.443 lift, 278/288 duration, 204/214@.050"


Edited by RSB on 05-07-08 07:40 PM. Reason for edit: No reason given.

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Loc: S. E. Ks.
Reg: 08-26-05
05-07-08 09:29 PM - Post#1428530    
    In response to RSB

sometimes running to high a gear ratio can work your engine harder and make it use more gas

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future projects
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Posts: 860
Age: 61
Loc: maryland
Reg: 02-27-05
05-08-08 08:49 AM - Post#1428757    
    In response to Datguy57

19 miles to the gallon! You should be happy! That's twice what I get babying the car!

1956 Chevy Belair

"14th Year" Platinum Supporting Member
Posts: 10657
Age: 65
Loc: Shaking and Burning!
Reg: 07-19-01
05-08-08 11:28 AM - Post#1428845    
    In response to jk56chevy

9 MPG city and 13-14 highway. Combined is the big question mark since I can't keep my foot out of it.
383, 700R4, 4.11's
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"5th Year" Silver Supporting Member
Posts: 2668
Loc: Lawrence, KS
Reg: 09-23-05
05-12-08 09:06 AM - Post#1431329    
    In response to HYPR

I'm getting 18.5-19.5 with my LS1 (Corvette/350HP) and 4L60e, 3:55 gears. I was hoping for 22-25. I only have 3000 miles on it, so I'm hoping it will break in and improve.

I had talked to some people getting in teh 20's. One guy had a 58 Chevy conv, and said he g0t 25. But, maybe it was a lower HP LS1, higher gears. I don't know.

I've been considering dropping in a higher ratio.

1956 Belair Convertible

Bubbletop Build Thread

Senior Member
Posts: 1100
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Loc: Covered in Oil N' Burnt R...
Reg: 12-14-05
05-12-08 02:00 PM - Post#1431495    
    In response to 56_Kruiser

I will drop in here and give my numbers to put this into perspective.

454BB 292H cam Performer rpm 830Dp Holley Ported Oval port heads dne 4 + 1 3.25 gears with 29" tyres.

Did about 500 miles this weekend and used £100 worth of fuel which equates to about 20 UK gallons or about 25MPG!

Admittedly that is mostly motorway driving at about 2800 rpm, 70mph, along with the odd blast up to 4000rpm, but even so that is not bad going.

Hell fire that even surprised me, who needs fuel injection.

Big Blocks Rule!!!!!!


56 Bel Air Sedan, aka The Pumpkin. 28 Years and nearly done!
56 Chevy 3100 Big Window Stepside,aka The Pumpkin Patch Speed Shop! Moving under its own power at last...

Edited by IsItDoneYet? on 05-12-08 02:02 PM. Reason for edit: No reason given.

Posts: 163
Loc: Fargo, ND
Reg: 01-04-03
06-05-08 08:48 PM - Post#1449560    
    In response to IsItDoneYet?

RSB & 57Tim,
Just found your post. Sorry I'm so slow.
What RPM are you guys turning at 60 or 70 mph?

Forgot this:
RSB. What size tires do you have?
57Tim. Nice looking car. What size tires on the front?
I'm also one of those 'mileage' type of guys. (Evidently there are only 6 of us on the planet) I'm trying to improve on my 19mpg, and I need new tires anyway.

"If it ain't got fins, it ain't a real car!

Edited by KOOL57 on 06-05-08 09:04 PM. Reason for edit: Because I can

Senior Member
Posts: 1064
Loc: Buffalo, NY
Reg: 06-13-06
06-06-08 06:04 AM - Post#1449681    
    In response to RSB

19 mpg seems pretty good to me, my everyday driver is an '03 minivan that gets 18 mpg and isn't nearly as cool as a '55!

'56 Chevy 4dr 210 327ci
'97 GMC K1500 Suburban 6.5TD

Frequent Contributor
Posts: 1456
Age: 74
Loc: Arizona desert
Reg: 03-10-04
06-06-08 06:25 AM - Post#1449690    
    In response to KOOL57

My '55 with a inline 292" motor, manual O.D. trans, & 3.08 axle runs 22.5 consistently on road trips. 55 MPH = 1600 RPM, after that it seems like 100 RPM = 5MPH. This is my daily driver & I use Mapquest mileage between gas stops to figure this. When my speedo quit yrs. ago I just let it be & drive by the tach. Next town N. is 90 mi.& its only 3 blocks long, going W. its only 60 mi. to next town. I get in 3 or 4 600 mi. trips to SoCal most yrs. Mileage has always been important to me. Doug

Honored Member
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Loc: San Francisco, CA
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06-06-08 08:17 AM - Post#1449749    
    In response to IsItDoneYet?

  • IsItDoneYet? Said:
Did about 500 miles this weekend and used £100 worth of fuel which equates to about 20 UK gallons or about 25MPG!

No fair! Your gallons are bigger than ours.

Actually, that works out to about 21 miles per US gallon, which is nothing short of amazing, considering your engine.


There's a line between good and evil no wider than a razor's edge - D.S. James Hathaway quoting from The Night Keeper

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06-06-08 03:31 PM - Post#1449993    
    In response to raycow

502, th400, 3.50 F9" rear, detroit locker, 31x18x15 MT radials, 8-10 mpg on road, 4-6 around town, 1 gal per run at the track.....
Need to do some tuning....
Maybe a smaller carb???

Senior Member
Posts: 8854
Age: 65
Loc: O.P. Kansas
Reg: 09-27-01
06-06-08 09:38 PM - Post#1450276    
    In response to IsItDoneYet?

  • IsItDoneYet? Said:
Did about 500 miles this weekend and used £100 worth of fuel which equates to about 20 UK gallons or about 25MPG!

Yeah, but you were probably heading South?

Five things that you cannot recover in life:

* The Stone after it's thrown
* The Word after it's said
* An Occasion after it's missed
* The Time after it's gone
* A person after they die

Dedicated Enthusiast
Posts: 5628

Reg: 05-27-08
06-06-08 11:11 PM - Post#1450309    
    In response to awsum55

'67 283 TH400, 3.08 rear end with 225-15 tires in a '52 Chevy gets 21 on the highway.
'57 283 TH200-4R in a wagon (no idea of rear end but it's stock) gets about 19mpg.
Problem with the '57 is that it has the stock low compression heads which don't bring the torque up any and the engine feels like it's lugging at about 1900rpm on the highway. The '52 is doing 2200rpm with which it seems fairly happy with.

Frequent Contributor
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Reg: 01-18-05
06-07-08 03:03 AM - Post#1450331    
    In response to 52chevybob

Bone stock 283 2x4 245hp with overdrive (5th). 16 mpg, mixed highway and secondary driving, plenty of WOT too.

1957 Belair 2Dr Hdtp, 58,000 original miles, original never rebuilt 283 engine, 245hp, Dual Fours, Tremec TKO 600 5-speed, 3.70 gears, AACA Senior in 1985
previous trifives:
1955 Belair Convt
1956 210 2dr Sdn
1957 Belair 2Dr Hdtp


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