6 cylinder milage threw the years?

[Tim]

hey guys,

just a random question, now a days alot of people go for a new 6 cylinder car for gas milage reasons, which as gas pirces jump and fall isnt realy a bad idea.

my question is this, do older 6 cylinders get decint milage or are they just as big of gas hogs as an 8.

examples 1954 235, early 1960s inlines ect

tia
tim

[Rocky]

I gotta little 6 cylinder story for ya, Tim... Once upon a time, my son and I decided to take both our chevy pickups from Omaha to Ogden, Utah. We were gonna attend the Golden States Pickup Parts hog rassle and show our stuff...look over a few other chevy pickups.
My 68 chevy shortbox used a freshly rebuilt 292 with a 3 speed overdrive and 3.73 gears..
My kid's 69 chevy shortbox had a well used 250 chevy 6 with a 3 speed, non overdrive...also had 3.73 gears. At the time, both trucks had the stock 1 barrel Rochester mono jet carbs and factory single exhaust with glasspack mufflers. Both also had later HEI ignition systems from later 6 cylinder engines...
I was just certain my truck, with it's overdrive, would kick his ass in the mileage dept. We rolled along at about 70 mph and my 292 was very happy at about 2500--2600 rpm. The Kid was buzzin along at the same speed but his engine sounded like it was winding up pretty good, maybe 3000 rpm or more. After about 150 miles, we pulled off for fuel. I was astounded to find his low-geared truck too exactly the same amount of fuel as my overdrive truck!
We kept track of our mileage for the entire trip and our mileage was almost identical at a shade over 17 MPG. He used about 4 quarts of oil and I used none.
My overdrive advantage was cancelled out by my additional 42 cubes....

[cornfieldrodder]

Dad's old 68 Checker could push 24 MPG with its 235 and 3 speed on the road. 15 was all it would do in town, though. The car was still getting good miles when he took it off the road with 230+k on the clock without so much as removing the head. My 66 Dart with a 225 and 3 speed would do 25 highway driving and averaged about 22. My 72 Demon was i little less with a 904 torqueflite. A freing put a weber progressive 2 barrel and 3sp with OD in his 65 Cuda. He claimed an average of 27-29, depending on the state of his ongoig modifications.
My 2.2 4 cyl, 3sp auto Acclaim gets 22. The old 3.0 O/D Plymouth my ex had got 27 average!

[Fat Hack]

From my own experience:

77 Nova 250 six/auto......16mpg hwy
68 Chevelle 250/auto......16mpg hwy
78 Nova 250/auto..........19mpg hwy (Holley 1v carb!)
76 F150 300/3spd 2wd......13mpg hwy
93 F150 4.9/5spd 2wd......14mpg hwy
76 Firebird 250/auto......18mpg hwy
77 Camaro 250/auto........17mpg hwy
78 Nova 4dr 250/auto......14mpg hwy
78 Monarch 250/auto.......16mpg hwy
86 Celebrity 2.8/auto.....24mpg hwy

It's my understanding that inline sixes never were super efficient, especially in stock form. Not to say that they can't be tweaked, but as you can see, they fare no better than V8 counterparts in my own trials for the most part.

[Bugman]

The stock 230 Flathead 6 three speed in my '55 Plymouth gets 14-16 city, 18-20 hwy.

-Jeff

[Tim]

thanx guys

any one have any idea what the 6's in an older army style willys/jeep would get?

tia
tim

[Deyomatic]

Our own Antichrysler was kind enough to lend me his 1959 Rambler to cruise to the Lone Star Round Up 2003. It was, I believe, a 195 CID straight six with an OD tranny. I got around 24 MPG in it.

[Jkustom]

My pretty tired '54 235 got about 19 on the freeway with the powerglide.....

[Machinos]

My '78 Dodge truck with a 225 slant six and OD got 24mpg at 85mph on a 5-hour drive last summer, with 160k on it no less. That's the only time I ever kept track, but if it can get 24mpg at 85 I'm sure it can get more at 65.

I think the trick is to have enough power that the engine doesn't have to scream when you're cruising. Really small late-model cars like a Geo Metro or whatever don't really get better highway mileage than city mileage beecause they have to work so hard just to keep going.

[PBRmeASAP]

I'm getting about 18 on my 235, 2X1's and a split manifold, and i'll cruise 65ish all day.