How come it's a need? you swapped the engine but didn't swap the matching cooling parts? Every SR20 has a fan and radiator and shroud that keeps it at the right temperature even when you are in a traffic jam. So something must have gone wrong.
Lots of info here for a new cable. But can't you just take your old cable to a cable shop and have a new one made? You will be sure it fits and saves the trouble of spending hours on the internet gathering measurements.