cat makes 3 basic versions of the 3126 low mid and high hp, if you can get a dealer that has access to cats web site they have a chart of the components required to uprate horsepower. if memory serves me correctly a 275 or 300 hp truck engine could be changed by using your ecm, but make sure the performance components are correct, that would be the injectors, turbo, cam and pistons, some also require a different vibration dampener, the rerate chart has this info.
that was a serious malfunction if you can see through from one side to the other. good luck in your search for a replacement