Yes, but they have a following like Mustangs so new parts are plentiful.

Interestingly, the first Toyota straight six was based on the 1929-1936 207cid engine rather than the Chevy 216/235cid. The later iterations of Toyota's Stovebolt were based on the 1939-1963 GMC 236cid

For the record, Toyota paid licensing fees to General Motors for the design.

1950 Chevrolet 3100 (Ol' Roy)

1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)