Does anyone know the cutoff year for the 7:31 R&P on the 915 trans?
Has anyone run a later 915 w/8:31 R&P on an early 911S? Any acceleration changes, any problems with running your engine hard, or daily driving?
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Does anyone know the cutoff year for the 7:31 R&P on the 915 trans?
Has anyone run a later 915 w/8:31 R&P on an early 911S? Any acceleration changes, any problems with running your engine hard, or daily driving?
The 8:31 R&P change came in 1976...
FYI ... They changed the 4th and 5th gear ratios for the later boxes.
Early 915:
1st - 3.181
2nd - 1.833
3rd - 1.261
4th - 0.9615
5th - 0.7586
Final ratio 4.4285
Late 915:
1st - 3.181
2nd - 1.81
3rd - 1.261
4th - 1.000
5th - 0.821
Final ratio 3.875
It also seems they kept changing the 5th gear ratio in the later boxes, maybe because of the increases in the cars weight.
Sorry, I have no experence with the later diff. in the earlier box