View Full Version : Inline Six Gas Milage?


1 shot
11-15-2006, 09:12 PM
Hey guys was wantin to know how many miles to the gallon you get if you have an inline six?
Im gonna buy one and rebuild it and was wanting to know if those of you that have them have any complaints?
Like over heating, or mechanical problems you've had with them and that kind of stuff.

Thanks guys:D

Let me know

41 mopar
11-15-2006, 09:43 PM
1. 64 nova w/230 Mercruiser motor single bbl split manifold,i get about 22hwy/ 18 in town. 2. 41 plymouth sedan 225 stock motor hwy 24 hwy, 17 intown. neither have heating problems. the mopar does have elec. fan. not great on power,will cruise all day pass my buddies at the gas station. I would not put 8 in these, dare to be different.

Fat Hack
11-15-2006, 09:49 PM
Most times, my old 250 Chevy sixes got about the same mileage as my 305 V8s, except for one that was equipped with an aftermarket Holley Economaster carb in place of the marginal Rochester Monojet...that car (a Nova) got excellent mileage...mid 20s on average!

On the plus side, Chevy 194, 230, 250 and 292 sixes will run FOREVER, and they get ya plenty toasty in the wintertime!!

Big Tony
11-15-2006, 09:59 PM
Getting about 18 in town and 22 or so on the road in my 235. As far as reliability goes those baby's are damn near bullet proof.

squirrel
11-15-2006, 10:12 PM
depends on what vehicle it's in, and gearing makes a difference too.

We get about 15 in my one son's 59 chevy truck, stock 235, stock 4 speed granny box, stock 3.90 rearend gears. Get about 19-20 in rural/highway driving in the other son's 70 camaro, stock 250/pg/2.73

Light/small car and overdrive can result in dang good mileage with a six.

Bugman
11-15-2006, 10:27 PM
I get 20-23 highway with my 230 Flathead 6 in my '55 Plymouth with a 3 speed and 3.73 gears.

Bluto
11-15-2006, 10:31 PM
GMC's both much modified! Both with overdrive trans and 3:90 gears in my 39 pick-up

228--- 18/25

302--- 12/20

plym_46
11-15-2006, 11:08 PM
I have a 230 Flat 6 MOPAR dual carbs, 3speed, 4.11 rear and 205, 75 15 radials. She gets about 18/19 regardless of manner in which she is driven. Looking as a pair of 225's for the rear to help her break the 20 mark. the 205's are about 1.5 inches shorter than the stock tires.

The stock 218 i took out was getting about 15 to 17.

RetroSpeed
11-15-2006, 11:24 PM
As long as I don't mash the "Go-Fast" pedal too often, the progressive linkage operates the center carb only on my Edelbrock equipped 200. On the otherhand, what's the fun in running a tri-powered six if you can't "light the hides" when the feeling hits.

49ratfink
11-16-2006, 01:57 AM
got about 16 in my slanted six dart. that's 200 miles a week on the freeway and then around town. that's real mileage. I had no gas gauge, so I kept track of my mileage and how much gas I got. always filled it up.

it was always in the 16's whether I did the math after a week or a month

rusty1
11-16-2006, 07:45 AM
...I've run many six cyl. cars/trucks, all very reliable and good on gas. Had a 48 Chevy coupe with Nova sub/rear w/ 3.08 rear gears, 225-15 tires and it knocked out22-24 mpg running a stock 69 Chev 230 w/ powerglide.
...What kind of combo are you planning on? That will make a difference of course.

HEATHEN
11-16-2006, 08:00 AM
...I've run many six cyl. cars/trucks, all very reliable and good on gas. Had a 48 Chevy coupe with Nova sub/rear w/ 3.08 rear gears, 225-15 tires and it knocked out22-24 mpg running a stock 69 Chev 230 w/ powerglide.
...What kind of combo are you planning on? That will make a difference of course.

My '64 Tempest 2 door with stock 215 six, three on the tree and 3.08 rear got a best of 24.6mpg at 65-70mph cruising to Carlisle (220 mile trip).

thunderbirdesq
11-16-2006, 08:30 AM
Seems like you've probably got the answer to your question already, but my '64 Econoline has a monobarrel equipped 250 with a 3 on the tree, 3:00 gears and it gets 22 or so on the highway. It's not the most aerodynamic thing on the road either. It's been nothing but reliable and makes plenty of power. I also have no gas gauge, so I always fill up and keep track of my miles meticulously. If I don't, I'm walkin...:D

243427

lindross
11-16-2006, 08:33 AM
Hard to say exactly without an odometer, but my 225 Slant get's approximatly 27-30 MPG.

spudsmania9
11-16-2006, 08:55 AM
Long time ago I ran a Gremlin with a 258. It got 18 to 20 MPG which increased to 22MPG with a 1bbl economaster holley.

Dolmetsch
11-16-2006, 09:12 AM
My 81 Lebaron 225 got a best of 31 to the Imp gallon with 30.5 being the norm for highway.
Our 66 Cuda with cam Offy intake , Holley 500 2bbl and hooker headers, ported head , 360 reworked valves and head planed 060" (car ran 15.80s in 1/4) could average 25 MPG (also Can or imp gallon) even at speeds of 70 mph and better. I checked it s driving from Orlanda Florida to first stop inside North Carolina. It was a 198 (75 engine) in the 66 chassis. Both cars were automatics.
To get US gal multilpy the miles per gallon by 140 /160.
Don

flatheadpete
11-16-2006, 09:14 AM
Long time ago I ran a Gremlin with a 258. It got 18 to 20 MPG which increased to 22MPG with a 1bbl economaster holley.
With my 5 carb, gnarly cam-havin' Amc motor, I'll be lucky to get yardage.....

34Hupmobile
11-16-2006, 09:17 AM
My old 250 with stock monojet, AOD trans and 3.53 rear got around 32 highway/25 city. My new 292 with quad and same trans and rear gets around 24/16.

cruisinkruty
11-16-2006, 09:28 AM
Chevy 250 sixes love H.E.I. ignition. Also the later Monojet carb is alot easier to tune as the idle circuit restriction tube is removable and can easily be opened up a bit for todays oxygenated fuels. Cutting the stock head to bump up the compression a bit helps too I usually do .060 on em.Three angle valve jobs with back cut intakes are a must as free horsepower and torque are gained there. Modifying your stock exhaust manifold for duals is a chore but once again,making a 6 breathe is the key to better performance and mileage. Do not eliminate the source of heat to the bottom of the intake manifold as the car will run like shit due to fuel puddling. People install aftermarket headers and eliminate the intake carb heat and then have to run the engine over rich just to have any driveability,alas gas mileage will then suffer. Gas mileage is a blend of efficiency of combustion,lack of parisitic horsepower loss,gear ratio and weight and tire size.

1 shot
11-16-2006, 11:36 AM
Im thinkin just bone stock for the time being, till get some extra cash to buy some other little after market goods to put on it....I've run many six cyl. cars/trucks, all very reliable and good on gas. Had a 48 Chevy coupe with Nova sub/rear w/ 3.08 rear gears, 225-15 tires and it knocked out22-24 mpg running a stock 69 Chev 230 w/ powerglide.
...What kind of combo are you planning on? That will make a difference of course.

1 shot
11-16-2006, 11:42 AM
Thanks allot guy's ill keep ya posted on the rebuild.

squirrel
11-16-2006, 12:00 PM
Hard to say exactly without an odometer, but my 225 Slant get's approximatly 27-30 MPG.


yeah, hard to say without an odometer, but you could just make up some numbers :)

wife's dart used to get 20-22 with the 225, but it had a working odo, which seems to hurt mileage noticeably

Hellfish
11-16-2006, 12:04 PM
I have a 55 235 in my 50 Chevy (3500 lbs?) and I think it has 3.7 gears, 3 speed trans, single barrel carb. I think I get around 18-22 with it. I've never had a problem with it. Runs like a champ and stays cool. Parts are easy to get at local stores, but may not be on the shelf

My 65 Econoline van is a brick on wheels.. lightweight, but a brick. It has a worn out 170 in it with all sorts of leaks. Truck gears. I get around 13-15 mpg in it doing 80mph. :D

lindross
11-16-2006, 12:25 PM
yeah, hard to say without an odometer, but you could just make up some numbers :)

wife's dart used to get 20-22 with the 225, but it had a working odo, which seems to hurt mileage noticeably

Not made up at all.

8 gallon tank, I know I drive 60 miles a day (summer of course) to work round trip. After 3 days of driving, I go fill up usually taking on 6 - 6 1/2 gallons of fuel depending on how far my foot was in it. ;)

The motor is in a roadster (check my profile) that weighs in around 1800-1900 pounds.

RacerRick
11-16-2006, 01:37 PM
My old Scamp got 31mpg on the highway with a stockish 225. It had a later super six 2brl manifold on it and a holley carb. Other than that, it was a 2900lb no power option lightweight, with a 904 auto and a 2.79 geared rear.

young buck
11-16-2006, 02:28 PM
my studebaker commander gets 25 on the high way...doin 60 mph with the stock 3 speed overdrive...it used to get about 28 but i have a carb off of a ford 300 six on it now...

HEATHEN
11-16-2006, 04:53 PM
Hard to say exactly without an odometer, but my 225 Slant get's approximatly 27-30 MPG.

When I was in college, I picked up a '66 Valiant for $200 for a school car. 225/904 Torqflite. It was good for 24/25mpg on the highway, and had good power for what it was--it's the only stock 6/automatic car I ever had that would spin the tires just from flooring it from a dead stop, without resorting to cheap tricks.

ianblaster
11-16-2006, 05:04 PM
I am getting about 16-18. But then again I have a 38 Ford rearend that is geared pretty low with a 3 speed tranny. It gets to 65mph really quick though.
http://i145.photobucket.com/albums/r222/ianblaster/IMG_5837.jpg

TagMan
11-16-2006, 07:09 PM
I got 23.9 mpg over all on my trip to Rapid City this September in a '37 Chevy coupe with a 235", stock 3-speed, OD in the torque tube and 3.73 gears.
Mileage can not be determined by the engine aone - you gotta consider vehicle weight, engine, cam, carburetion, tranny, rear end ratio, driving habits, etc. Lotsa variables.

Hellfish
11-17-2006, 10:23 AM
A friend of mine has a carburetted 80s chevy v6 in his 39 coupe. I don't know what MPG he gets, but it's pretty damn good.

1 shot
11-17-2006, 10:11 PM
Well it seems that these are really awsome engines to run, thanks for the oppinions guys.

OldSub
11-18-2006, 12:30 AM
Well this is a late entry, but I'll add my two cents anyway.

My basically stock GMC 270 with a granny gear 4-speed and 3.08 gears in a 3500 pound Suburban gives me 14 to 16. About the same as my basically stock 350/350 with 3.70 gears in a 1/2-ton pickup.

1 shot
11-18-2006, 12:37 AM
Kool

relli
03-12-2010, 05:05 PM
I have a 64 chevy biscayne that I drive every day. I ran the original motor w/ the weber 2 bbl and split manifolds. That motor was burning oil so I pulled a low miles one from a 69 nova. It has the mono jet carb(rebuilt) and the stock exhaust manifold and is getting better mileage the the other set up. 18mpg.

Pontius
03-12-2010, 06:05 PM
My 51 hardtop with the original 235/pg got about 15 no matter how hard or easy I drove it.

29nash
03-12-2010, 06:34 PM
Don't care as long as the gauge keeps working. I burn gas for the fun of it.:D
Out of curiosity I checked my truck (weighs 2800) with 250 chivvy a year or so ago. Rochester B pot bellies-twice on Offy manifold, single straight pipe, 403 rear, mostly around town, calculated 17.

carbking
03-12-2010, 06:36 PM
Ford 300 CID in van got about 14~15 highway with the original Holley 1 barrel.

Upgraded to a 400 CFM Carter 4 barrel and highway mileage jumped to 22-23. Then we got E-10 in Missouri and mileage dropped below 20.

Engine was pretty much bullet proof. in 420 K miles, no significant problems other than normal maintenance and ignition modules. Changed the *&^%$# ignition module enough times to carry a spare. Head was never removed from engine in 420 K. Finally scraped after it rusted out the third time (don't you just love the idiots that salt the roadways in the winter?)!

Replaced it with a vehicle with points and condenser! Points and condenser last as long as the *&^%$# electronic ignitions, and are a bunch cheaper!

Jon.

B Blue
03-12-2010, 09:08 PM
Back in the days of the 55 mph speed limit, I had a Gremlin 232 3 speed with a high mileage cam and stock carb. It would get 28 mpg at 55-60 mph. The Gremlins had 22 gallon gas tanks, that 550+ miles/tank would bust dang near any bladder.

Bill

Trucked Up
03-12-2010, 09:22 PM
yeah, hard to say without an odometer, but you could just make up some numbers :)

wife's dart used to get 20-22 with the 225, but it had a working odo, which seems to hurt mileage noticeably

LMAO grew another one and promptly LMAO again.......:D