Has anyone on here done a cng conversion on a Dodge Ram 5.7 Hemi with the MDS Engine? If so,how did it work? I am wondering if these kits will allow the mds to kick in properly reducing down to 4 cyl. operation. Also if anyone has done one of these were there any other problems. What kit would be the best to use? How was the performance on cng? Also is the stock internals going to hold up over the long haul? I have heard about hardened valves/seats and was wondering if these new engines came factory with the hardened valves or should they also be added. I heard that some of the older chevys had problems with this.