Tunnel/Diff changes in '65

[Bruce Melvin]

From what I can piece together in '65 the pinion flange on the differential was increased in size; in diameter. Was the body's shaft tunnel also increased in size?
How was the drive line shaft different?

Thanks,

Bruce

[Mike M.]

Re: Tunnel/Diff changes in '65

no the floor pan was identiacal, whether it was a 396 or a 327.

[Bruce Melvin]

Re: Tunnel/Diff changes in '65

The reason I ask is that an individual who makes his living selling corvette parts made the statement that a newer (>'64) differential could not be used in a '63 or '64 because there was not enough room for the larger flange and U-joint. He was very arrogant about it as if it was fact and obvious.

Thanks,
Bruce

[Joe L.]

Re: Tunnel/Diff changes in '65

Bruce-----

It is true that the 63-64 pinion (companion) flange was different than the 65-67 (and 68-70 with manual trans). Primarily, the difference was due to the different spline configuration used for 63-64 as opposed to 65+. However, the overall configuration of the flanges was otherwise a bit different, too. Both flanges use exactly the same size u-joint, though, and, in terms of overall outer diameter, the flanges are about the same size. I can't imagine that there would have needed to be a difference in the tunnel configuration as a result of the change of flange.

The thing that most often causes interference between the driveshaft and the tunnel in the area of the pinion flange is cracking of the floorboard structure in this area. It is a VERY common problem on mid-year Corvettes.