I would like to know which Mercedes (car)models were available in the
USA in 1978/9. If there are many the larger vehicle would be
preferable. Any models definately identified for this period would be
helpful.

Dear lily351,

In the 1978/1979 time frame, twelve Mecedes-Benz models were available in the USA: 


450SL (Roadster; chassis 107.044, engine 117.985 V8); available from 1976 to 1980

450SLC (Coupe; chassis R107.024, engine M117.985); available from 1976 to 1980

280SE (Sedan; chassis W116.024, engine M110.985 I6-dohc); available
from 1977 to 1980

450SEL (Sedan; chassis W116.033, engine M117.986); available from 1976 to 1980

450SEL 6.9 (Sedan; chassis W116.036, engine M100.985); available from 1977 to 1979

300SD (Sedan; chassis W116.120, engine M617.950); available from 1978 to 1980

280E (Sedan; chassis 123.033, engine 110.984 I6); available from 1977 to 1981

240D (Sedan; chassis 123.123, engine 616.912 I4); available from 1977 to 1983

300D (Sedan; cassis 123.130, engine 617.912 I5); available from 1977 to 1981

280CE (Coupe; chassis 123.053, engine 110.984); available from 1978 to 1981

300CD (Coupe; chassis 123.150, engine 617.912); available from 1978 to 1981

300TD (Station Wagon; chassis 123.190, engine 617.912); available from 1979 to 1981


Hope this will be useful!
Regards,
Scriptor




Sources:

Mercedes-Benz U.S Models
http://home.hiwaay.net/~gbf/mbmodels.html

B & B Autoparts: 1978 Mercedes Model List
http://www.mercedes-autoparts.com/1-mercedes-1978.htm

B & B Autoparts: 1979 Mercedes Model List
http://www.mercedes-autoparts.com/1-mercedes-1979.htm