#21

11-13-2013, 08:51 PM

Half-Inch Stud Half-Inch Stud is offline

Ultimate Warrior

Join Date: Jul 2000

Location: BlueBell, PA or AL U.S.A.

Posts: 18,889

Yep. Long ago our 70 400 GTO 3-speed stickwith 2.54:1 Type "O" rear would pull >20 MPG Highway. crazy good MPG from 16 heads and 068 cam.

Efforts to beat that all failed, except my former 455 (48 heads) & big 252 @.050 cam, Th400 into 3.31:1 rear would shoe excelleng highway MPG yet terrible backroad MPG.

I finally figured on OVERLAP EGR as the great equalizer. So my 68 GTO (455, 9.0:1) 236/244cam, Th400 into 3.54:1 rear do both backroad & highway MPH terribly.

And that is why the OVERDRIVE trans is in process.

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