http://members.rennlist.com/chuxter/901&915ratios.htm
Gear Ratios for 901, 911, 914 & 915 Transmissions
901 Ratio 915
3.182 AZ
X A 3.091
AA 2.833 BY
B 2.643 D
C 2.400 E
2.214 DV
D 2.188 FZ
2.059 GZ
E 2.000 EU
1.933 ET
4 F 1.889 HY
G 1.833 HX
6 GA 1.778 HW
H 1.684 JW
HB 1.632
HA 1.600 KW
I 1.550
J 1.476 LV
K 1.429 LU
1.381 LT
L 1.364
M 1.318 MT
4 N 1.261 NT
6 O 1.217 NS
P 1.174
1.167 OS
Q 1.125 OR
R 1.080 PR
S 1.040 PQ
T 1.000 QQ
U 0.9615 QP
X V 0.9259 RP
W 0.8888 RO
X 0.8571 SO
Y 0.8214 SN
Z 0.7931
0.7860 SM
6 ZA 0.7586 TM
4 ZD 0.7097
Norm 4.4280 Norm
Opt 3.8570 Opt
NOTE: marked gear sets are the standard gears for 914/4 and 914-6
901/06 A HB S Z
901/07 A F M U ZD
901/75 B GA M T Y
901/76 AA E I M O
901/77 AA F J O S
901/78 C HA O T Y
901/79 B HA M R V
901/12 A HB S Z
901/13 A F M U ZD
901/80 B GA M T Y
901/81 AA E I M O
901/82 AA F J O S
901/83 C HA O T Y
901/84 B HA M R V
911/00 A HB S ZA
911/01 A GA O V ZA
911/80 B GA M T Y
911/81 AA E I M O
911/82 AA F J O S
911/83 C HA O T Y
911/84 B HA M R V
914/11 A F N V ZD
914/12 A F N V ZD
915/10 AZ HW OR SN
915/00 AZ HX NT QP TM
915/01 AZ HX NT QP TM
915/12 AZ HW OR SN
915/02 AZ HX NT QP TM
915/03 AZ HX NT QP TM
915/10 AZ HW OR SN
915/11 AZ HW OR SN
915/13 AZ HW OR SN
915/08 AZ HX NT RP TM