The TR3A is fitted with a larger 2138cc engine than the its predecessor the TR3 which had a 1991cc engine
The TR3 replaced the TR2 in October 1955. Over its lifetime it was uprated to TR3A (1957), the first British car to adopt front disc brakes. Its engine was rated at 100bhp at 5000rpm. A model designated as TR3B was built specifically for the US market.