97 civic hx hessitates on accel please help =(

[BishiRST]

Hi, I have a 1997 honda Civic HX 5 speed that was in a wreck. I don't know how it ran before the wreck but it runs like crap now!! I replaced the entire front end to include the hole radiator support and went with the 99 front end. before I took it appart I realized the condenser fan shroud slashed the oxygen sensor wires and the car had an engine light and ran like crap, I replaced the O2 sensor and got the light to go off, after driving it for a few weeks i realized it started overheating and blowing the coolant into the overflow bottle so I thought the thermostat was stuck since the car sat for nearly 3.5 years, so I took the housing off and there was no thermostat, so I put one in, the overheating continued and then I realized the coolant smelled like fuel, so I replaced the head gasket and T-Belt, put everything back together and ran it, the overheating stopped while driving but if I let it sit like at a drive thru, it rose past the 3/4 mark, but when I got going it dropped under 1/2. Now the problem is on take off, the car feels like something is hoplding back the power, like the A/C compressor is on while your trying to move off, but its not working since the condenser is not mounted, but then you get past 3000 RPM's and it feels normal like what ever was holding the engine back let go and the car picks up like it should but it does this through out the gears 1st thru 5th. someone said that the cat was bad so I changed the manifold to a catless one and it still drives the same, I'm lost with this problem, I can really use some advice if anyone has ever came accross this hurdle, please help