I to this day do not understand why Pontiac didn't offer GTO with the 421? Pontiac's official position was that 389 was the biggest engine available? The 421 would have fit. And one would think that some special option could have married the two to possibly be the most iconic Muscle Car of all time? Today. 1964 GTO does have the destination of being the first Muscle Car by many circles. But not #1. Today. #1 is still debated. But a 1964 Super Duty GTO may have had that title?
JMO.
