I sorted out these numbers on-line as it looks like I will be adapting a Merkur T9 box to my Alfa Romeo engine.
Appears to not be too hard, a spacer type adapter should do it without any welding.
I may have to slightly relocate the top two Alfa bell housing bolts.
My intent is to be able to use an unmodified Alfa clutch assembly with only the driven disc changed or modified.
Pretty clear I will want the Cosworth first gear upgrade.
Ford Sierra (Merkur) T9 Gearbox Ratios
1st : 3.65
(2.95 on Cosworth version - available as a modification to standard boxes)
2nd : 1.97
3rd : 1.37
4th : 1
5th: 0.82
Alfa Romeo Gearbox Ratios
Number of gears: 5
Gear ratios (overall):
1st : 3.304 (15.05)
2nd : 1.988 (9.06)
3rd : 1.355 (6.17)
4th : 1 (4.55)
5th : 0.79 (3.6)
R 3.01
Speed range
Alfa (max speed on gears, top gear value theory 4.55 diff).
(km/h/mph)
I: 47 / 29
II: 78 / 48
III: 115 / 71
IV: 155 / 96
V: 197 / 122
1000rpm speed:
(km/h/mph)
I: 7.8 / 4.8
II: 13 / 8.1
III: 19.1 / 11.9
IV: 25.9 / 16.1
V: 32.8 / 20.4
Final drive ratio std: 4.555
Standard tires: 165 HR 14
Alfa rear gears.
USA version Spiders.
69-79 - 4.56, 41/9. LSD from 1972, optional in 69 & 71. No 4.10 option.
80-94 - 4.10, 41/10. Manual gearbox.
Adding a pic of my geometry for the Ford T9 to Alfa adapter.
