ISX to X15 swap headache. PLEASE HELP

[Orangecar89]

I have a 2015 International 9900i my father bought at auction. Truck is in pretty good shape structually. I believe the truck came with an ISX, and a good guess would be it dropped a valve, regardless, it now has a 2017 date code X15 in its place. I have a laptop with INSITE on it and with just clicking around, I feel like everything is mix matched. The engine according to the valve cover is 450hp/1750 tq CPL 4342, build date 05/17. The ECM has 2350 EF10054.42 stamped on the side. According to what I found, the engine serial number doesnt match between the valve cover and what is in the ECM. The ECM code according to INSITE is 10044.76. We drove the truck home 400 miles and it didnt use a drop of DEF, but it didnt smoke either. Im assuming is has been DE-MANDATED. Any help would be great. The truck ran fair going down the road, but was low on power, it idles erratic and hard starts. We aren't trying to jack the power up. Just want it to run good, if we could actually get 450hp/1750 tq that would be great. Im fairly confident the exhaust has been gutted due to a welded on patch, so I will have to work around that. I am very new to INSITE, so if you could walk me through or link me to a thread on how to download the program so it can be reviewed, that would be great. I wouldn't have purchased this truck, but for the price and physical condition my father did and now we are stuck with someone elses project. Once again, thanks for any help and thanks for allowing me to join. I posted this in the PC help section also.