The first Celica was built on a platform shared with the Carina sedan and sold in North America specifically to answer the Ford Mustang: a stylised 2+2 coupé body over ordinary sedan mechanicals.[1] Its US-market engine actually got weaker as the generation aged: the 1975 facelift’s larger 2.2-litre 20R made less power than the original 1971 car’s smaller 1.9-litre 8R, a result of mid-decade emissions regulation rather than any change of intent, and the article says so plainly.
Both trims recorded here are the North American-market engines, since those are the ones the article gives complete power, torque and year ranges for; the Japanese-market twin-cam 2T-G and 18R-G engines are mentioned by name but without power figures in this article, so they are not recorded as trims.