What you need is a tach that goes to 15,000 RPM, with the redline starting at say, 12,000 RPM. This way you can take advantage of that truck engine's torque and not have to shift as much.

About your belt thing. I'm willing to bet since you rev'ed the engine so high, the belt slipped. Be it, it was loose before hand, or just to much for it to take. I wouldnt doubt it if the belt is off a tooth or something. Smoking means rubbing.

My buddy blew up his dodge ram driving conservatively on the highway. The oil pick up screen apparantly has a huge flaw in it.. it gets gunked up, and starves the engine for oil. If you take that engine above the factory red line, its a matter of time before it goes ka-poot. Also, who knows what RPM the stock water pump cavitates at. I'm guessing well before your 7000 rpm fun zone.

Last post for this thread, alchohol is the only thing I like killing my brain cells.