Check to see if you have a long plastic air inlet snorckle in the fender of the truck, remove it if you do. There is info in the FAQ section of the forum about this.
Also Check in the 6.2 forum they may have some good ideas of how to get hp from a NA engine.
There maybe problems going to turbo on a 94 and newer because of the difference in sensors (turbo engine would have more) and ECM, possible also the fuel pump couldn't increase fuel enough to compensate for the turbo. You have a rare NA truck, many mechanical 6.2's have been changed to turbo but I don't think many 6.5 ECM controlled engines have been. Hopefully someone else with more info will let you know on that.
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