Well according to the information on the Russian EPC North America got a 3.92 rear end on the 1976 230.4

See the EPC diagrams via EverythingBenz - Mercedes-Benz Forum and Web Search Using Google

I'd go and see the differential on the car in question

Scrape off the lower left hand corner of the diff casing right next to the rear cover to see the marking for the final drive ratio. You could be in luck.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!