94 celica st overheating issue, 1994 celica st 1.8L overheating issue. Options

[rapid36]

Hi i have a 94 celica ST with the 1.8L motor. I bought a used motor from online that had 132k miles on it. i dropped it in and i replaced the following on the car:
1. rear main seal
2. oil pan gasket
3. torque converter
4. radiator swapped out with 3 row performance radiator meant for gt4.
5. added a 15 row transmission cooler
6. new air filter
7. new spark plugs
8. new spark plug wires
9. new front o2 sensor
10. new fuel filter
11. straight pipe headers
12. high flow cat
13. aftermarket muffler
14. new belts all the way around

and so when at idle everything seems fine and when i drive around town everything is fine but only when i get on the highway going 65MPH it starts to overheat very quickly and then i pull over and let it idle and it seems to go back down then i drive again and then at this point going any speed is making it overheat. i have no check engine light. and i checked the thermostat and it works and i checked the water pump and it works. i just flushed my cooling system and no luck there. I dont get why its overheating on me. I checked the compression and all cyclinders show 150. no noises are being made and when it gets hot the car runs fine no missing or other issues just gets hot. Anyone have any ideas?

[rapid36]

strange. i looked in the book and they didnt give a specific range of what was acceptable but they did say that they all should be consistent. if not then i would have problems. they are all consistent in my case, ill do more research online and see if i can get a better idea about this. also im guessing that the coolant wouldnt leak in if the exhuast gas has pressure and is forcing itself into the cooling system which might be why im not seeing any coolant inside my cyclinders and thank god im not cause i dont want to risk hydro locking it. so far its all positive i cant wait for the test tomorrow. hopefully it wont be a slap in the face and at the same time if it does show negative then at least i know what i would have to do to fix it lol. so i got mixed feelings about it.