I have a 98 Chevy C2500HD with a 454 and 4L80E. I was wondering if anyone had some information, thoughts, done it before, anything about swapping to a diesel engine. I know the 5.9 12 Valve is a popular swap, but I was wondering about doing a 6.5 or 6.2 swap. Is there any advantage to swapping in a 6.5 or a 6.2? Can they be modified to get more power? Because I know stock the 454 came with more power and torque than both the 6.5 and the 6.2. Also looking to swap the 4L80E for a manual transmission. Any information would be greatly appreciated.