Instead , a total of 30 cars were built , including a development car tested with Alfa Romeo 's 2.5 - litre V6 engine and a nearly - complete Mark 2 prototype of the same .
Plans were to build as many as 40 cars per week .
A total of 30 cars were built , including a development car tested with Alfa Romeo 's 2.5 - litre V6 engine and a nearly - complete Mark 2 prototype of the same .
Plans were to build as many as 40 cars per week .