I've never really cared about mpg (still don't really) but I guess I was a little surprised that my '71 442 is getting about 10 mpg average lately. Granted, it's been miserably hot for a month so I have had the A/C running constantly and have got 'into it' a couple of times but gee-wiz. My 454 Chevelle used to get around 14 but then again it wasn't nearly 2 tons either. Oh well, I can't complain because the 'smiles-per-gallon' are off the chart.

 

That is AWSOME!

 

it's the ethanol

 

I can promise you it wasn't that far from it.

10-12 would have been about normal for a 442 back when gas was gas. But yes, reformulated gasoline and high ethanol content gasoline plays hell with gas mileage on a car that doesn't have electronics to compensate for rotgut fuel.

That's what I don't understand about this EPA voodoo. If you're burning 30% more fuel to travel the same distance, I fail to see how emissions can possibly be reduced enough to offset the extra fuel consumption. And then they beat the drum loud about reducing oil dependence. Boolshat.

People who buy into and believe that mumbo-jumbo will swear there's a problem with the car causing poor fuel mileage, but my old K-Car (god rest it, and I STILL hate Bambi) and the 81 Pontiac Catalina Safari wagon I had could both prove that wrong. On real gasoline, the K-Car consistently delivered 29 mpg. If it got hold of a tank of RFG or ethanol, the mileage would drop to 21-22- a full 28% reduction in fuel mileage. The wagon got a consistent 24 mpg on real gasoline. RFG/ethanol would drop it to 17- a 30% reduction in fuel mileage.

It happened too many times to believe it was anything but the fuel, and the results were the same on different brands of fuel. And both these cars had engine management electronics.

 

but what good is the engine management if your 2 cars mileage dropped with bad gas too? I can understand on older, but were the engine management on yours too primitive?

 

I have heard that about the reformulated gas. The new gas also lacks the 'boil-off' additives which makes starting after 5-10 minutes of 'hot soak' REAL fun. I have to crank it with the pedal to the floor sometimes. Is any brand better than another or are we stuck with what's available?

 

Well- 81 all GM had was C3/C4 and an electronic QuadraJet, and 87 Chrysler EFI. So yes, I suppose they were primitive.

The 97 Bravada I had was a little more forgiving, but not much. Fuel mileage didn't suffer as much on RFG as throttle response and performance. The 93 F150 can tell the difference sometimes, but I can tell the difference between 87 and 93 on that one performance-wise.

The point is that this emissions fuel is not as efficient as pure gasoline. Ethanol doesn't have near the BTU rating as pure gasoline. You cannot travel as far on the same amount of fuel, so you're burning more of it. But, the corn lobby is very influential in Washington.

Mumbo-jumbo and voodoo, like a lot that comes out of government agencies promoting agenda-driven science.

 

Let's keep this post non-political please.

 

i bet miserably hot with ac will knock you down 1-2 mpg.

in 20+ years my 69 442 has been pretty consistent at 10-12 mpg around town on super-unleaded without the ac on. highway has been 15-17. most of that was on a quadrajet. the bolt on edlebrock runs about the same.

coasting skillfully can get me an extra 1 mpg typically, so i bet using your ac in hot weather (poor performance) is costing you.

that's my experience on summer gas. in my other cars i consistently found "winter gas" would kill mpgs...

my old subaru legacy would drop from 24 city to 17 city on winter gas, 30+ highway to 26 highway. same with saabs.

i wouldn't complain about 10-12 on a big block 442 unless you had been getting 14 on the 442. wait until fall and measure a tank when the temps drop.

 

My 67 is getting 7 to 9 & w/air on Steve

 

I get 9-10mpg in my 4-speed car with a 4:33 gear.

 

9-10

 

12-14 mpg on 94 octane with ethanol in my 69 442 4-spd. with 2.56 rear...and huge boots

 

I'm averaging around 14-16mpg with my 350, without the A/C on. I would have thought it would be better, especially when my 401 cubic inch Riviera gets at least the same mileage, weighs more, and is faster.

 

Wow after reading this I definitley need to make improvements. Interesting about mine. When my previous owner installed a 600 edelbrock, it shifted like crap and he took it to a shop. There they tuned the carb saying it was running super lean. They richened the hell out of it, but not so much that you can smell it being 'over rich'.

The real problem was the stock carb has a special linkage for the slim jim (I learned this after the fact). After I got it, it shifted WAY early, so I played with the linkage to get a better shift. Unknowingly, my slim jim didn't like that much, and well it died. I cut to the chase and put in a 700r4. Now..with that overdrive trans...I'm getting about 12mpg on the freeway using the fillup/mapped gps method.

I plan to use the FAST self learning fuel injection. It's simple, adaptable, and not particularly expensive, though not "cheap". I read an article about a nova where they improved the mpg something like 50%. Though any ill tuned/pumped up car can have mpg improved.

After the install I'll do a posting on here to show the steps and improvements.

 

Seems like you should get better gas mileage than that, especially with an overdrive transmission. If you go to fuel injection I'm sure that will do much better.

 

Well I don't know what my Olds gets for mileage and really don't care. i don't drive as though concerned about getting the most mileage for my buck , more like turning the most heads to get those inside smiles. i do care about the mileage my Colorado gets and it sucks for a newer smaller truck.