run the car and get it up to temp. most tuners will tell ya to work on the high speed first. the os v spec is a three port motor with the best carb but when it starts to get lean this motor will starve for fuel and slow down. make a couple of passes and bring the car in, it should come down to an idle right away. pinch the fuel line next to the carb it should stay at the same rpm for about 3 seconds. if the bottom or the mid's not right the top will also be effected. make a couple of passes to check the top end and try richining the top and see if the car slows. if it does then lean it,go slow with the needle adjustments,no more then 2 hours at a time until top speed. keep checking the bottom.