Is a 1973 nove parts interchangeable with a 1973 omega?

yes they are!nova was the class of cars gm put out.nova stands for nova,omage,Apollo,ventura.and aside from grills and motors everything bolts right had habits of barrowing from other divisions if one ran out of parts.chev motors in Pontiac and Buick cars and so forth seats,headliners hoods.hope this solved your Q.