I purchased my 08 SD slightly used with a 40 tooth rear sprocket. The previouse owner flipped the guide blocks that fit over the axel 180 degrees in order to get the stock chain to fit, therefore shortening the wheel base. With the stock 17 front and 40 in the rear it wants to wheelie all the time, I can't image how yours will act with a 16/40 combo along with the shortened wheel base. Let us know how it feels.