Buick 300 MPG

I have been tuning on my 1967 Special with the original 300. Car has just shy of 24k original miles, has 1965 4bbl intake, Edelbrock 500 carb, dual exhaust through magnaflow mufflers, Petronix distributor at 36 degrees total timing, clutch fan, 3.23 gears with posi and a 3 speed saginaw, I just added factory aluminum drums on all 4 corners, that took 40lbs of rotational weight off the car. Manual steering and brakes, AC is currently removed. I just filled up today and with interstate driving at 65-70MPH the little Buick got 22MPG!, I could not believe it that a little 300 in an A body would get such good mileage! I hope someone can use a bit of this information, still waiting to go and have the car weighed, Its a post car so im guessing its 3,100-3,200 lbs.

 

I bet 25mpg with 2.56 or 2.73 gears

 

Even if the car was 3400 lbs it only takes 47 Hp to sustain 70 mph on level ground.

a 300 cid 2bb motor can do that easily along with good mpg.

 

I was getting 17-18 mpg all around driving with a 83 Riv that had a307 Olds motor ran good plowed thru snow lol
But I would say that is great mileage for big car and small motor justas good as todays small suv. you will be 3550 lbs just a guess

 

i wish i got 300 mpg

 

I had a '69 Camaro, 327 4 speed car that turned low 15s. I got 23+ MPG.

 

I had a 64 Special 300 4 speed Muncie, 3.23 rear and typically got 21 MPG. That car weighed 2950 thanks to the aluminum heads and intake. I was in the the Air Force making $2.00/hr and doing a lot of interstate driving so I put a 225 V6 and a 2.78 rear in it and got 25 MPG. I currently have a 65 Special 300/300 that gets a solid 19.5 MPG. I also have a 65 Skylark factory 225 V6 ST300, I plan to either put a 200R4 or a Saginaw 4 speed with over drive in it. My goal is to get 30 MPG.

 

Imagine what it could be with modern port fuel injection. Like a 62 Skylark with Hi-comp 215 V8, 200R4, fuel injection, synthetic fluids, radial tires....

 

I have a 300 in a MGB that weighs maybe 2700 lbs with port injection, cruise control and overdrive. I recently got 24mpg out of a tank but I think it was a fluke, normally 20 is the best I can hope for.

Jim

 

Hard to believe, but I got 23 mpg from my '69 Camaro 327 with a 4 speed, on the highway.

 

My 66 Jetstar will get 20 mpg on the highway. Thats got a 330 with an st300 and 2.78 gears. Thats a fullsize..

 

Who says you need a computer and fuel injection to get great fuel mileage

 

Back when my wildcat was stock with 2.78 gears


We drove it from Green Bay back to tenn
65 /70 mph and got 19.7 mpg
This was on real gas not the ethanol mix

Now with the 462 and 2.78 gears and ethanol
I am lucky to get 12/13 mpg

Scott

 

a well tune engine with highway gears and a stock like cam i think makes the biggest difference for gas mileage.

 

I would try the non ethanol gas to see if the gas mileage would go up