the speedo could be off. have you checked it? first check the odo. run on the interstate and look at mile markers. one mile should be one mile... period.

if the odo is correct then put it on 60 and time a mile by the interstate mile markers. should be one minute. if not the speedo is off. btw do it when there is not much traffic.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.