What are the condition of the studs, and are they just carbide trail studs i'm guessing? If it were mine i would be running 144 in that 600 but maybe you will be able to get it to hook up, just have to know what to do. It will take a lot of center spring preload (crank it up quite a bit), a lot of transfer rod setting, and just enough limiter to get it too hook. You don't want tons of limiters out for racing because then you will get too much ski lift and it will actually lose traction then. Also a moderately set rear spring, and loose front springs (tied down if you are seriously racing).