Quote:
the "312" designation suggests a 3.6 liter engine (12 cylinders, 300cc each) scaled down to 1/3 size, so it is a 1200 cc engine in the model.

Calculating again, aren't we?

If you scale down a 3.6 l engine linearly to 1/3 size, would you not get about 133cc (3600/(3^3)) ?