A super GTO. This crazy idea was created after Ace Wilson's Royal Pontiac, a Pontiac car dealer in Royal Oak, Michigan, offered a special tune-up package for Pontiac 389 engines. They decide to create a bigger and powerful engine for Bobcat tune up and they choose 421 SD unit. It very rare to find any GTO with this engine but there's a chance to fit 421 SD in GTO because 421 SD is an dealer opt in every full size Pontiac. The car itself is very fast and probably the fastest GTO ever made before Ram Air V came out. It can reach 164 mph while 0-60 mph is able to hit 4.6 sec from Muncie M21 4 speed 3.23 final. Also, it rumored this car created by Royal Pontiac is not just to become the leader on drag strip but also to confront it's cousin from Italy. Thought they never meet. Car and Driver test this car and they able to reach 12.8 sec @ 112 mph for 1/4 mile.