1980 was a long time ago but some of your information is erroneous. There was no 4.3 liter V-6 produced in 1980. The 1980 Chevrolet Camaro V-6 offerings were for a 231 CI (3.8 liter) Buick engine for the California market and a 229 CI (3.8 liter) engine for the other 49 states. These engines were typically anemic in performance with 110hp and 115hp respectively. General Motors did offer a 4.4 liter V-8 in 49 state configuration but I have never seen one personally.
There was offered a 3-speed manual gearbox but again, this was offered as an order option for mating to the 115hp, 229 CI engine only. Of the 26,679 Berlinetta Camaros produced in 1980 I'd hazard a guess that to find a 229 CI, 3-speed manual gearbox equipped version would be quite the endeavor.
As for the 133 MPH run... don't forget that 1980 ushered in the wonderfully stupid 85 MPH speedometer in GM's attempt to conserve fuel with their psychological warfare. Plus, the top perfoming V-8 powered Z-28 had a recorded top speed of a mere 120 MPH. Maybe you were reading the speedometer in Kilometers/hour??