No power

I just bought a 87 gt a couple weeks ago and finally started racing it. In first gear when I hit about 4,000 rpm the engine revs high but it feels like there is no power. This happens when I just take off from a stop without launching. around 3,000 it pulls hard with full throttle but when I hit 4,000 rpm, it seems as if the wheels might be breaking loose. It seems to do it for all gears if I am into it all the way. Please let me know if there is a problem I dont know about.
Thanks

P.S. What's the best shift point for the car? The redline is at 6k, but it feels like it dies at about 5.5k.
 
is it a 5 spd? could be the clutch slipping at high rpms. drive down the road at like 25mph and put it in 4th gear and ease into the gas and see if the rpms go up but the car doesnt go any faster.....but yeah, get a new fuel filter because it could be starving for fuel