ok yesterday i finally drove my car an hr away i was scared as **** cause i didnt want anything to happen to it. anyway the temp line was about 3/4 the way up the whole way. and i had no acceleration i could only go about 60. and the line just stays at 3/4 but i've installed everything new. fan, pump, even the 2 sleeve alternator pulley. but still it overheats. i was thinking it was the mufflers that they were clogged. cause whenever i'd punch it, the needle would start to rise. but then whenever i would slow down the car would start to cool down. what do you guys think.

 

Do you still have the cats?

 

Your symptoms are what I had last year. My 87 was showing the same symptoms. What finally fixed it? Would you believe the water pump housing? The aluminum casting behind the pump was eroded by the turbulence of the high revving pump. The bypass valve seat under the thermostat had about a 4mm chamfer eroded away, and there was a 6mm hole eroded through the wall between the inlet and outlet side.

All this bypassing gives symptoms like a partially blocked radiator. I fabricated repairs with Bondo Marine Epoxy Putty Stick. It has held for a year now.