i have a sohc turbo setup in my car stock rad(i kno gets hot) when i get into full boost the car started to overheat. i did a compression test 200 across i pulled the rad cap to see if there was buildup after i ran the car and no blowby. someone told me to just retorque the headbolts since they are arp's so i retorqued them and the bolts towards the dist were loose. after that i burped the coolant again and switched the rad cap from a diff car i have and took it for a drive. after abuot 30 mins of driving i pulled up to a parking spot and let it idle and sit the car started to now overheat while at a stop. i pulled the rad cap off and backpressure now within the radiator! i switched the rad cap and burped the system again and took it for a drive let it sit at idle in the parking lot for 20 mins now no overheating. i am scared of a hg gone but could there be any other reasons maybe why the car tends to overheat i kno having a stock rad and stock fan on a turbo car isnt the best thing but i havent had many overheating issues until of late. does it sound like i solved the problem tho? or wat else could i try to fix the overheating issues.

thanks
cliff