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1970-71 B body 383-2 gas mileage?

Posted By: ragtop

1970-71 B body 383-2 gas mileage? - 09/06/16 12:01 AM

What kind of highway gas mileage are you getting with a 1970-71 B body 383-2. These cars came std. with the 2.45 rear axle.
If your car came with an optional 2.76, please state that, if you are replying with gas mileage figures. Thanks.
Posted By: forphorty

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 12:28 AM

I could be wrong, but I think 2.45s didn't come out until the mid 70s, 8.25 rears only.
Posted By: a12rag

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 12:33 AM

Nope . . the 2.45:1 came on the highway package in 70 on the B bodies. I had 2.45s in my 74 duster360 . . . it has the original e58 360 4bbl and 727 auto ... 235/60/14 tires, running at 70mph, rpm is 2600rpm . . . got 22mpg all day long !!! I know, not a b body or 383, but should be in the ball park ... . .
Posted By: Alaskan_TA

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 12:36 AM

1970 B-body gear ratios at http://www.hamtramck-historical.com/images/dealerships/DealershipDataBook/1970/70_Coronet0029.jpg

1971 B-body gear ratios at http://www.hamtramck-historical.com/images/dealerships/DealershipDataBook/1971/71_Coronet0024.jpg
Posted By: forphorty

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 12:38 AM

Didn't realize that it went back as far as 70. Had a couple A body rears with 2.45s. Was I correct on the 8.25 rears only part?
Posted By: mdwyer

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 12:39 AM

71 charger 500 383-2: 8 1/44 2.45 gears/
changes dp4b / holley 600 / dual exhaust mp dis. rest stock!

highway 19.7 mpg, cruised great at 75 mph with 28 inch tires

wish i had it back

mike
Posted By: NANKET

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 02:46 AM

It really depends on how you drive it, go easy on the gas pedal and just cruise and 20 is possible. I put 2.94 in mine. 205/75/14 tires.
Posted By: ragtop

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 02:55 AM

Originally Posted By mdwyer
71 charger 500 383-2: 8 1/44 2.45 gears/
changes dp4b / holley 600 / dual exhaust mp dis. rest stock!

highway 19.7 mpg, cruised great at 75 mph with 28 inch tires

wish i had it back

mike


Great info with all the specs.
Was your 8 1/4 rear axle stock? I was not sure if those 2.45 gears were 8 1/4 or 8 3/4 rear gears.
Posted By: mdwyer

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 03:07 AM

yes factory 8 1/4 (2.45), cast crank 383-2.

bought from original owner in 2004 with only 67000 miles on it.

it was VERY original. EV2 a/c buckets console
Posted By: ragtop

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 04:24 AM

Originally Posted By mdwyer
yes factory 8 1/4 (2.45), cast crank 383-2.

bought from original owner in 2004 with only 67000 miles on it.

it was VERY original. EV2 a/c buckets console



Thanks. One more question. What size and type tires?
Posted By: mdwyer

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 04:44 AM

235-70-15 front
275-60-15 rear

both bfg t/a
Posted By: a12rag

Re: 1970-71 B body 383-2 gas mileage? - 09/06/16 04:14 PM

Only 8 1/4 rear, not 8 3/4.
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