1973 mustang coupe 2000 miles on complete engine rebuild at J and J Performance. Its not really a 1971 boss engine but all parts are the same number are, not but it's really a kick in the ass to drive. In some ways its much better than stock because it so smooth up to 6 grand on the tack, that’s because the engine is balanced blueprinted all the bob weights for the pistons, rods and crank are documented.