What was the biggest engine you could put in a 1972 nova?
The biggest engine generally considered practical and readily adaptable to a 1972 Chevy Nova is the 454 cubic inch (7.4L) big-block V8. While larger engines *could* be shoehorned in with significant modifications (even a 502 or larger), the 454 represented a relatively straightforward swap, requiring less extensive fabrication and modification than larger options. A 454 from a donor vehicle (like a Corvette, Impala, or truck) would be the most realistic approach for a street-able Nova.