I have a 2003 ford explorer with a v8 engine and i was wondering what parts i can use from it on a 2007 ford explorer sport trac

 

The 2003 and 2007 were different models, but the 2007 also had the V-8 so much of what you have should transfer. I'm not sure if the difference between them was just cosmetic or extended to the frame, etc. Others, with more experience should be along to clear that up.