Using the Russian EPC on EverythingBenz - Mercedes-Benz Forum and Web Search Using Google I've come up with this for you.

(This is how I started to compile the data presented in the thread I've linked above)

I've had to make some assumptions.

I'm assuming the 190E is a 201.024 chassis

Mercedes Benz EPC 201.024 Chassis Information | Everything Benz

and I'm assuming the 300E is a 124.030 chassis

Mercedes Benz EPC 124.030 Chassis Information | Everything Benz

From the links above you can see that the W201.024 had the 722.400 transmission and the W124.030 had either the 722.320 or the 722.358 transmission

Digging deeper you can find that the differential on the W201.024 has a 1:3.23 final drive and the W124.030 had a 1:2.87 final drive - so from that I can say that the shift points will be a bit messed up.

Back to the question - specifically will it fit

The engine fitted to the W124 is a M103.983 / M108.980 starter on the LHS of the vehicle

The engine fitted to the W201 is a M102.961 / M102.962 starter on the LHS of the vehicle

So it looks good.

This is as far as I can take you as I don't have grown up EPC ('cos it costs money for non US residents!)

I can't compare or check adapter plates for you (I assume they exist).

__________________
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!