Unless he had a tranny swap with different gear ratios, I dont see how. Also, I know he had 17" wheels, so that will throw his speedo off. Another thing. At anything above 100+mph, your speedo will be off. Very off. Thats why I go by the tach. If his speedo read 170, he was probably doing about 155. Also, the speedo only reads to 170, how could he see it reading 172?