I was just investigating that whilst you were posting.
I hadn't actually noticed your reference to the 1953 TR2 engine before - sorry.
I saw the site where you got the information from; they really should know better!
It was the only site I've found so far with a full description of the car, so either they meant it has a TR2 chassis and engine (they also called the chassis a 1953 TR3...) or else it was a later, perhaps crashed, TR3 base.
The only other reference I found to its engine said it was a TR5..
Funny how the passage of time clouds history, and it's also funny how errors keep getting repeated until they become the gospel truth!