at normal driving I don't see any smoke but when i hit a hill or accerate hard and black smoke comes out and doesn't seem to stop till I let off the throttle. what could be causing this?

low boost pressure. Read the Faqs at the top of the forum page. It's pretty common on a 6.5L to lose all boost when the vac system fails.

i would start with checking the vacuum lines, vacuum pump and wastegate solenoid. i think you should have about 25+ inches of vacuum at the pump. that sounds like the same thing that happened to me ended up having to put a new pump on.

S engine's have to have that pump for the EGR/baro, but put in an F prom and block the exhaust ports to the intake and you have an F engine and you can remove the vac pump, and solenoids (resist the MAP and the WG solenoid isn't missed). The vac system is the weak link to boost control.