In the mid 70s, a customer who drove a lot serviced his car at our dealership. He drove a 1975 Plymouth Voyager with a 318 V8. He was insistent that we not touch the carburetor claiming he was getting 35 mpg on the open highway.
I use to own a 67 Camaro (327 4-speed manual) and a 69 Firebird (Pontiac 350).
I bought the Camaro right when I got out of the Army and started college. And right about then we had the first oil embargo. Gas prices went form $.35 to .90 in less then a year. I had sold my Vega…and the Camaro was my only transportation. I tried for about 4 months to get the best possible gas mileage I could…The absolute BEST I could get was 24 highway. I kept my speed down…made sure those extra 2 barrels of the quadrojet never opened…Kept it properly tuned…it ran great. I might have been able to squeeze another 2-3 mpg out of it…but NOT 8…and if the 327 couldn’t get 30…I don’t see how the how the 427 could.
He must also be using several “miracle” products, like water injection, a “Tornado” intake fan, and rare earth magnets on the fuel line…in addition to the imagined effect of no catalytic converter…
But seriously, the only way this engine is seeing 30 mpg is if it’s powering a motorcycle…
“in addition to the imagined effect of no catalytic converter…”
That brings back memories from my younger days.
The older, Eastern European men who populated the town where I lived in the mid-70s would purposely put leaded gasoline into the tank of a new car, right after they bought it, in order to “burn out the cat converter and get better gas mileage”.
Of course, they did not improve the gas mileage of their land yachts, and wound up cursing a year later when emissions testing forced them to…you guessed it…replace the catalytic converter that they had purposely destroyed. It’s always amazing to me when people adamantly believe that they understand something, when in fact they have no clue about it.
I remember reading about a person who owned a 1970 Monte Carlo with the 454 engine in it. Said he got 30mpg with it at one point, but his speed never went above 30 miles an hour to get that and was in overdrive ASAP.
I would take that Monte Carlo story with a grain of salt unless the MC has been modified. They never came from the factory with an overdrive transmission.
One of my bosses had a later model Monte Carlo V-6 ,which he claimed extreme gas mileage(I was feeling pretty good about getting 33 mpg on a Pinto Pony on a trip-Boss said shoot that aint nothing,then he preceded to blow me out of the water with his mpg claim on his sporty luxury car.Every noticed how some of these cats who get super mileage seem to be at the gas pumps as often as you?-Kevin
If you have to limit yourself to 30 MPH to get that kind of mileage, you need to sell your car and get a moped. All the people driving behind you will thank you.
Dear old dad says the same thing, “Back in the 60’sI got 30+ driving a Mercury that weighed 4,000 pounds with a three speed with an overdrive and highway gears…” of course he also tell me cars back then would start at -30 or colder with just a touch of the key. I smile and agree. Not worth the fight.
I could see 30 mpg going down a steep hill, but other than that no way.
If you have to limit yourself to 30 MPH to get that kind of mileage, you need to sell your car and get a moped. All the people driving behind you will thank you.
IIRC it was one of those things they done just to see if they could do it, not something they did all the time.
Larger engine displacement does not always mean lower gasoline mileage. In 1951, a Cadillac “61” with its 331 cubic inch V-8 under most conditions would get better mileage than a 1951 Chevrolet with its 235 cubic inch 6 cylinder engine pulling the “PowerGlide” automatic transmission. A 1959 Studebaker with the 259 cubic inch V-8 engine could do as well if not better under most conditions than a 1959 Studebaker with the 169 cubic inch 6 when both cars were equipped with the same transmission. Also, some 4 barrel carburetor may get better mileage than a 2 barrel carburetor on identical engines if one isn’t flooring the accelerator to open the secondary barrels. However, I’m not sure of the 30 mpg claim of the 427 cubic inch engine.
Gas Rhonda never made any mileage claims…But he sure had a lot of fun !
Years ago, I had a late 70’s Pontiac 9 passenger wagon, with of course a V-8. On the open highway I got around 17 or 18 mpg. A joker I worked with claimed he always got 25 mpg on his. That was pure nonsense.
A Sunbeam with a 427 is not a restoration, it would be an extreme modification with a purpose built subframe and many body and fender , fire wall, and hood modifications. They did make a Sunbeam that looked like the Alpine with a Ford V-8. It was a Sunbeam Tiger and it had a 260 cube V-8 a far cry from a 427.
Andy Rooney owned one.
Is the car idling and sitting on a trailer going highway speed, getting that mileage?
@Tridaq: A 4-bbl with small primaries and secondaries that only open at a certain throttle angle will probably do pretty well. I have the V8 version of my car, and it only gets a couple miles less per gallon than the V6 version. The V6 is just outclassed in such a heavy car.
Remember reading the mileage in old “Popular Mechanics” car tests,back when you actually had a choice in engine sizes and options,etc. Anyway the smallet v-8s would often have about the same gas mileage as the large engines in heavy vehicles or very close-terrian makes a difference too. everybody around here gets the same or better gas mileage with hi-po V-8 s as I do with a V-6(took 3.2 gals of ethanol free gas to go 72 miles yesterday)-Kevin
Triedaq is correct about engine size not being the determining factor in regards to fuel mileage.
My memory seems to recall someone posting recently on this forum about a 2012 Corolla (?) about which the complaint was 17-19 MPG city driving or something like that.
My heavy V-8, rear drive Lincoln gets 19 in town while having much more motor and weight to shove around.
And there’s always the Top Gear test run where the 400 Horsepower BMW got 2 MPG better on the track than the Toyota Prius.
What car is it installed in?
I am very familiar with the 427 in vettes of that vintage.
The Corvette has one of the best drag coefficients for cars of that era and is a fairly light vehicle. If any car can maximize mileage from the mini-rat, that would be my choice. Although neither I, nor anyone I have ever known, has ever considered gas mileage in these cars, let alone the maximizing of it. It’s more about Smiles/gallon!! That being said, the advertised mileage was combined 8.9 mpg for the L36 power plant/drivetrain, best of around 13mpg for exclusively expressway travel. My own experience is around 10mpg unlesss you’re really getting on it and then the gas needle can kick up a breeze…
30mpg? First off, who would want to do that to a BBC motor? Like tying a noose around the race horse’s neck so they don’t eat too much. I’d be doubtful of the claim unless it was significantly modified to achieve this level of fuel performance. In it’s original form, no way.
Maybe he’s testing the mpg by coasting on a long downhill, like from the top of Pike’s Peak or something … Next time he comes home making this boast, check, see if his brakes are smoking hot? lol