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.

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

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 ... . .

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

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?

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

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.

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.

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?

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

both bfg t/a

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