JHP .
Rake is usually refering to the difference in height between the front and back of the truck. So if the truck has 1" of rake, that will imply the back is 1" higher than the front. Negitive rake would be if the front was actually higher than the back. ( not good).
" poke" is the amount the tires stick out passed the fenders, generally done with offset wheels. Hope that helps. Most trucks will have a couple inches of rake, so when you load it the truck becomes level. If you dont have enough rake, the truck will handle poorly with a load.
Good Luck
E