I went though all the bens at the local Advanced Auto Parts in Maryland and i ended up w/stant part#13947 for my 300srt8 6.1. It is an 63 mm stock and the 13947 is a 64mm. I did very little grinnding on the outer edges to make it fit. but here is the kicker, on the 13947 stat u have to cut of the bottom sealing valve. it is copper so it cuts like butter. My car runs at the mark between 0 and 200 when moving now. I did get the fan mod from GSM to. Good Luckdtpracing said: