It's pointless to shoot for the huge HP numbers on these trucks, converting to DI heads? PSD injectors...I'd just get a PSD if thats what I wanted, but I think 300-400 is something we could achieve with better turbos and fuel delivery. This has already been somewhat proven, not just by NMB2 but the guy on the FTE forum that had a dyno slip saying 296HP. One of the big problems, and I know this is not an orignal idea of mine, is that the bolt on turbo kits were designed in order not to blow up a stock or near stock engine. Once the head gaskets and bolts are upgraded, the next limit is the wrist pins and just how big a problem that is is up for debate. According to Mel, that is what stopped Flatlander's compound turbo truck and I remember hearing some anecdotal stories about flattened wrist pins on the old non gated turbos especially when I first joined over at the diesel stop. Ford and IH probably upgraded those on the factory turbo IDIs and the PSD for some reason though.... I've discussed with other members about boring the pistons since they are forged aluminum but that also might be trading one weak spot for another one by removing some meat from the piston pin bosses. Your thoughts?