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Old 05-14-2008, 01:27 PM
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ericwy ericwy is offline
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Join Date: Nov 2004
Location: Arlen, Texas :)
Posts: 497
Default 400 TAs & gas mileage

What's a reasonable expectation for gas mileage for our 400 equipped TAs?
GM offered 2.41 gears for better mileage during post oil embargo 70's.
What kind of mileage to you all get with 2.41 or 2.73 gears with a 400 ?

I am getting about 15mpg city driving with the combo listed in my sig and I use
the secondaries ALOT. (sorry no highway mileage #'s yet) I was getting 11-12mpg
before putting in the OD 700R4. I am Planning on installing some 3.42 gears to bring
the final ratio up from 2.156 to 2.394 while in OD similar to GMs 2.41 final ratio.

__________________
1977 TA 400 9.5:1 CR 351hp 414LbFt, #13 Heads + 1.52 Roller rockers, 1968 Pontiac 400 intake, Holley 4165 650 DP #7054
Howards Hyd .447/.467 IN:288 EX:298 214/[email protected], MSD6A + MSD timing control + H2o/Meth
1-5/8" headers, Magnaflow 200CPI Cats + 2.5" Pypes X, Dynomax STs, TH-700R4 2200 stall, 3.42 Eaton 10-bolt, PS/PB/PW/PL/AC/Cruise
[email protected] 2.18 60' on P255-60-R15 radials, pump gas, mpg : 21.5 hwy 15.2 city