What is a 3 letter Pontiac model originally made from 1963–1974

A 3-letter Pontiac model originally made from **1963 to 1974** is the **GTO**.

### Details:

* **Pontiac GTO** is considered one of the first true **muscle cars**.

* First introduced in **1964** as an option package for the Pontiac Tempest.

* Became its own model in **1966**.

* Production continued through **1974** (as a traditional muscle car; it was later revived in the 2000s).

So the answer is: **GTO**.