Look, I'm all for the turbo stuff, but I don't think that's within the scope of what DRTDEVL is asking for.

The TB/plenum upgrade *may* net you 5 hp overall, and 3 hp peak. It helps, but not a lot. The MSD probably won't make any difference in top speed either, based on your current mods (although I like, use, and recommend their stuff).

Another thing to consider is adjusting your cam timing a bit. If you retard the cam timing you will shift the powerband higher (and advancing cam timing will shift it lower). You need an adjustable cam gear, and 2?-3? would be about the right adjustment. This would shift peak torque 300-600 rpm higher, and when combined with a gearing change, may be enough for what you're after.

I would also agree with Roger: I think this is a gearing/aerodynamics issue. The drag coeficient of the pickups is pretty awful, and this becomes a real problem above 65 mph, never mind 80+ -- it's boxy coming and going, with a face like a bulldozer and a rear bed that traps a lot of air. There's not a lot you can do to the front of the truck, but installing one of those net tailgates in the rear may help a little. A tonneau top would probably help, too, but the net gate is a lot easier.

Also, if you can do anything to smooth the undercarriage, that may help a bit. But really, I think correcting the gearing, and possible plaing with cam timing, will be the biggest bangs-for-your-buck.

-Jeff