What is the torque on head of an 84 celica GT?

There's no single torque specification for the head bolts on a 1984 Toyota Celica GT. The torque will vary depending on the engine (which specific 2.0L engine was in your Celica GT - there were several variations) and whether the head is being installed new or reused.

To find the correct torque specification, you MUST consult a factory service manual specific to your vehicle's year, make, model, and engine. These manuals provide detailed procedures and torque values. Using an incorrect torque can lead to head gasket failure or cracked cylinder head, resulting in significant engine damage.

You can find a factory service manual online (often as a PDF download) or through automotive parts stores. Searching for "1984 Toyota Celica GT [engine code] service manual" will likely yield good results. The engine code will be stamped on the engine itself.