What size tires are you running with what axle gearing? I like the 27 spline if you are running 35-38 inch tires...this way you can carry your old birfs as spares. With bigger tires than that though, you might want to go full out with the 30 splines. I believe that all of the superlongfield kits (27 and 30) do not need the martack...I think there is a bulge machined into the shaft to serve the same purpose?
