Exchange final drive I=43:11=3,91 for 320i from 09/1985 up to 09/1987 only manual gear box without cat, you need 1 for 1 car and for 320i from 09/1985 up to 09/1986 only manual gear box without cat only for country version I, you need 1 for 1 car

BMW Sedan 320i, 323i, M3 (E30)