The B210 fuel economy champ was the 5-speed model. From 1976-1/2 through 1978, it had the 63-series overdrive, and a raised port cylinder head -- an A14 with round-ports!

This was the 50mpg model! (correcting my above statement)



50 mpg B-210 Plus

The number one factor for Sunny fuel economy was not aerodynamics, which were all bad like every 1970s car. The #1 factor was lowering the engine revs to cut down on pumping losses in the engine.

The B310 best was only 47mpg. I don't know which engine it was we got A12A, A14 and A15 models.