So, Can you have a Old-Style carbed V8 and get 25+ MPG?

Can we have our "Cake-and-Eat-it-too"?
Do we have to subcum to Late-Model EFI engines to get Power and Great Gas mileage?

Can we have a 3, 4, 6 carbed engine that will produce excellant Gas Mileage? Oh yea, if you block off all but 1 or 2 of the carbs.

Butt, are we not HotRodders?

Can we Ingeniously created power and mileage?

 

http://www.jalopyjournal.com/ubbthreads/showflat.php?Cat=&Number=287379&page=&view=&sb=5&o=&fpart=all&vc=1

 

With overdrive, sure!

 

Some will say that "If you can't afford the gas find another hobby." I think this is a valid and timely question though.

Our gas hasn't hit $8 per gallon (yet) and we are probably lucky to be paying only $2 per gallon but damn, that still hurts at the pump.

Throughout my Hop Up "brick" the authors and advertisers repeatedly mention fuel mileage. It mattered then, it matters now - for some.

JH

 

Ed...Thanks for that link, very interesting reading.

 

Harrison:
I know what your saying, and I love to drive my HotRod and I'm in the planning stages of my "A" sedan.
I just want to enjoy it, and not feed it $200 a weekend!

 

Power and mileage are NOT mutually exclusive goals...go to the Tech-O-Matic and read through my 305 Chevy post...the faster the car went at the track, the BETTER it's highway mileage got!

That's because I concentrated on strategic engine mods using bolt-on parts to make the motor more efficient, hence making more power and providing better fuel economy.

(I could have stuck a set of 4.11 gears and a loose converter in the car and gone FASTER through the quarter mile...but fuel economy woulda gone into the toilet! I stuck with a stock trans and converter and the standard 2.73 "highway gears" in the rear axle!)

With progressive linkage, carefull tuning, and a calculated approach, I know I could build a multi-carbbed small block V8 that would deliver 25+mpg in a lightweight little rod equipped with a stock converter (or manual trans) and 2.73-3.08 gears out back...a car you could drive daily and esily live with.

I'm just trying out an extreme scenario involving a TINY engine in a rather big car right now to see how it works out...since I just want a cruiser, not a race car...and want it to be as light and fuel efficient as possible!

Gearing and torque are the key...along with any mods that make your engine more EFFICIENT. When I first bought that old 305 powered tank, it took nearly a quarter throttle to keep it moving at freeway speeds...once finished, the mere weight of your SHOE would hold it at 60mph...producing impressive mileage figures indeed!

By contrast, my daily driver these days is a little Chevy Metro. People see it and say "Oh! I bet that thing gets 40 miles to a gallon!"

I WISH! It's a four cylinder model that's geared to provide good "pep" around town...but it spins WAY too many rpms at freeway speeds to deliver decent highway mileage!

Around town, or on two lane stretches of road where speeds can be kept around 40-45mph, it isn't TOO bad...maybe getting a best of 25-28mpg on a really good day with the air off. Take it up to 70-80mph "real world" freeway speeds and it sounds like a squadron of Zeros in a constant power dive...and DRINKS the fuel...maybe 21mpg at BEST!

Ironically, the big 307 Olds V8 powered sled it replaced got 23mpg on the freeway all day long at scarcely above an idle! (And it was FAR less punishing on my fragile old body!)

I'm gonna try 2.73 to 3.08 gears in the back of my Fleetline with the Vega motor and a three speed automatic...might not LEAP off the line, but I'm very curious to see what kind of fuel mileage it delivers!

 

FATHACK:

Have you exercized this approach with say a 400 CID or larger engine?
Curious.....

 

Sure. My dad built a mild (and much-maligned) Chevy 307 with a Crane Cam and a 2-bbl. that gave acceptable performance and delivered 26 mpg all day long in a 39 Chevy sedan delivery. Aerodynamics of a twice-used brick.

That same engine with well-tuned headers and 3-2s with progressive linkage would give much the same economy and more power in a lightweight hot rod --

Steve.

 

AHotRod...

I built a 396 (402 really) powered 70 Chevelle back in my teens with a four speed and 3.90 gears. The car had BIG tube headers on it with no exhaust (my neighbors LOVED me!), an HEI distributor, mild cam, Holley Strip Dominator oval port intake, 780cfm vacuum secondaries four barrel Holley and an all steel 2 door hardtop body.

I didn't keep the car long enough to really iron out the full combination, and I was more interested in going fast back then...but I do recall that I was rather impressed when I drove the car to Detroit Dragway and made a few passes then drove it home and checked it's mileage...it averaged 18mpg...and that involved a few low 13 second passes and one or two that got into the 12s!

(The car's all time best pass was 12.42 with some fancy footwork on slicks!)

I think with some effort and tuning, I coulda pulled 20-22mpg out of that heap on the freeway!

Not bad for a big block four speed brawler!!

(But around town, the way I USUALLY drove it...it got more like 11-13mpg!!)

In retrospect, I think if I were doing the same car today, I'd opt for 3.31 gears and a dual plane intake with a closed dual exhaust system...maybe slow it down to the 14 second range, but make it quieter and more streetable!

But I'm pretty mellow these days!

 

FATHACK:

I'd even try a 4L80E gearbox today!

 

Yeah...I think I'd also attempt to run a 5-speed trans in place of that old Muncie if I were putting the same car together today...I'm actually pretty easy on drivetrains, so I think it'd live!

 

My dad usta borrow his dad's almost new 50 ford club coupe to drive between northern Oregon and central California. Had a stock 239 flathead with 4.11's and an overdrive. He was blown away to get 26 MPG on one stretch but I'll bet he was feather-footing it in overdrive at about 50 mph.
I had a well used 307 in my 72 nova 2 door. With a 350 hp cam, Q-jet, Muncie and stock gears [3.08?] I got an average of 18 mpg on the interstate between Omaha and norther Oregon....lota mountain driving involved on the trip

 

I had a Buick 350 in a T-bucket back in '79, and with a T350 trans and 8" Ford w/ 2.79-1 gears, it got 27 MPG....and ran the 1/8 mile in 7.3 !

 

Lets put this into perspective. Most folks drive Minivans, pickups, or SUVs in my part of the world. I think you would be hard pressed to find one of these that topped 25 MPG. My 2000 Ford Ranger gets about 18 most of the time. My 54 Chevy with a way too rich 650 on a mild 350? It gets the same!? I am going to make a provision on the Touring for a dash mounted Vaccum guage, I found a cool one the other day that had the vacc. measurements as well as fuel mileage guides printed on the face. I bet most of us could up the mileage of our dailys OR hotrods by 3-5 MPG if we used a Vacc. guage. GO READ C9s? Tech in the Techomatic.

 

[ QUOTE ]
I had a Buick 350 in a T-bucket back in '79, and with a T350 trans and 8" Ford w/ 2.79-1 gears, it got 27 MPG....and ran the 1/8 mile in 7.3 !


[/ QUOTE ]


You might have gotten 27 mpg, but you didn't turn 7.3 1/8ths with a 2.79 gear.

Mutt

 

Cool T...........I scored a vacuum gauge from a 69 Olds 98 with the big ol' letters "Oldsmobile" on the face and a brushed aluminum housing....has a light in it and everything! I'll get rid of the lettering and put it somewhere in the poncho.....I'm sure I can achieve 25-30 MPG with this setup, running 3.23's...

 

Mutt:

Ya wanna bet?

 

AHotRod:
Yeah, sure. Let's hear the specs on this wondercar. My T has a 406/350 and 4.11's and I can only muster 7.1 - 7.2 1/8ths - and while that's admittedly launching soft by flashing the converter, I shift at 6200, and my shift light comes on just as I hit the traps, so I know my car is dialed in pretty good.

Mutt

 

I've looked through this thread, and there is one obvious choice no one has mentioned yet. The Oldsmobile 307 coupled with either an o/d auto or a 5 speed manual (there has to be a way to do this, maybe a b/h from a 260?) in a lightweight car should pull off phenominal mileage. I've owned two - a 81 Buick LeSabre with no o/d and an 85 98 with overdrive. The Buick got 23-4 mpg and the 98 consistently 27 mpg. and that was pulling around 4000 pound tanks. There were also guys aroound here that swapped them into their 5.7 diesel trucks when they blew up and got stupid good mileage - that had to do with rear end gears in the mid 2's with the diesel. I am sure other Olds manifolds and parts interchange. This is something that I'm sure should be explored. Anyone done the Merc frame swap with a 307 Olds in the car??

 

Yes I did it this way[back in 1971]
I had a '39 chevy sedan [2960lbs] with a 283 bored 40 small chamber/small valve 2 bbl 283 HEADS on it.
It had a 327-350Horsepower HYD cam.
1-7/8" exhaust -duals/glasspacks.
It was running the stock 59 chevy intake made for a WCFB and [I used the WCFB Carter carb][small cfm's?].
It had a sychro 3 speed tranny with a 3:23 rear gear and a 26" tall rear tire.==============NETTED-25 MPG.

 

My Chevelle sure doesn't get it. I get 12 to 14 MPG on the freeway at 75 to 80 mph. I'm only running a 350 with Edelbrock performer cam, performer intake and 600 cfm performer carb. I have HEI. This is with 2.73 rear gears and a shift kitted turbo 350. Runs and idles fine, pegs the speedometer at 1/2 throttle, but mileage sux. You'd think I could at least pull 18 mpg on the freeway. Of course, I'm at 4950 ft here and usually go UP from there, but still... Any ideas? Think maybe my secondaries are partly open at freeway speeds? I already tried changing the jets and metering rods for my alt as per the Edelbrock chart.

 

My 51 F-1, 3200lbs, 390, factory tri-power, C-6, 3.00 gears. Pro built engine, 9.5 compression, polished rods, balanced, blueprint bla bla..Runs 1/4 mile best 13.20 @ 105. Can get 20 mpg on the freeway if I try, I never do, gets about 11 in town. I love the sound of two more carbs talkin. BAAAAAAAAAAAWAAAAAAAAAA!!!!!!......OLDBEET

 

Rocky's dad might have been feather-footing that '50 Ford to push mileage into the mid 20s, but real-world good economy can be coaxed from the antique architecture and design of the L-head V8 with some modern technology applied.

My pal Terry Griffith has a '50 Ford coupe with a near-stock 8BA that regularly returns 25+ mpg at 65-70 mph highway cruise without any conscious feather-footing. Terry has been building flatheads for himself and others about as long as has Vern Tardel who's been his best friend since they were kids, so Terry knows how to put together and tune 'em.

Aside from its expert assembly and tune, Terry's flathead is carburetted by a Holley 2300 350-cfm 2-bbl adapted to an Offenhauser 4-bbl manifold. The ignition is a GM-HEI conversion, and the motor breathes out through a pair of rare, large-volume rear-dump Ford cast-iron manifolds connected to high-flow turbo mufflers.

While the motor package makes a good contribution to the economy, Terry feels the big gain is found in the Mustang T-5 that couldn't be better spec'd than it is for the naturally torquey flathead. Terry installed a Maverick V8 8-inch rearend (originally equipped with a high 2s final) and runs a 3.50 pumpkin. The tires are radials all around -- also mileagae improvers, which is only an incidental factor in choosing them when the handling and ride quality they provide is considered.

Hard-core purists might piss and moan about the HEI and the alternator and the radials, but Terry's coupe is a no-apologies sweet driver that is appreciably quicker than it was when it began life. And it's certainly a lot stingier with the bang-water, plus it's a decent-looking pile . . .

 

I think to get 20+ takes allot of Feather-Foot driving too !

 

Its really quite simple guys......One factor would be elevation. [here in the highest hill in this town] is 25 feet above sea level!
Two -you need small displacement like the 239" flatty or my 292 small block of old days.....
and third you need 9-1/2 or better compression and small valves/ports/runners/CARBURETOR.
a small runner intake fed into small combustion chambers[higher comp] thru small valves=better intake air speed at lower RPM[CRUISE SPEED].
You can get more power with the additional cubes that a 355" or larger motor offers -with larger lower compression combustion chambers and larger runners in intake and heads-WITH larger valves/EQUALS=slower intake flow speed[read lower atomization rates] at low RPM highway speed operation.=less efficient.
JUST MY SHADE TREE RATIONALIZATION FOR THE END MPG RESULT I GOT.
GAS was also fairly cheap at that time[59-69CENTS] but fuel costs were an important factor to me then as well ,Cause I was driving exactly 25 miles ONE WAY to work [six day]s a week.[MY pay check was proportional to the then'71 gas prices at a take home amount of roughly $80.00 A WEEK!

 

Eighty bucks a week??? Damn, that'd be FINE by me TODAY!

Two bucks a gallon ain't so terrible...even my broke ass can handle THAT!

 

Hack-I wish I could kick this evening CHOCOLATE MILK habit I have.....its 5 dollars a gal!

 

[ QUOTE ]
Mutt:

Ya wanna bet?

[/ QUOTE ]

Yes I do - I really want to hear how to have an 11.5 second car with 2.79 gears that gets 27mpg with an Oldsmobile V8. I've been wasting a lot of money with my setup. Thanks..

Mutt

 

1 1/2 years ago we began talking of this, so what do you think now?

Can we get 25 - 30 MPG in a Buick 401 Nailhead powered fenderless Sedan, Coupe or Roadster ????