Did you know? The A-319 and 737 have really similar engines?

With a large 737-800 fleet powered by the CFM56-7B, it was a no-brainer that American would select the CFM56-5B for their new A319s. Both engine types share a common core, where they differ is the fan- the -7B used on the 737NG is just a -5B with a smaller fan, but differences in the fan blade aerodynamics and engine software offset what would be a less economical engine due to its smaller fan. The fan on the -7B is 60.5 inches in diameter to fit the underwing 737 nacelle but the taller landing gear of the A319/320/321 means the -5B gets a 68.3 inch fan. There are some differences in the core, but many core parts are interchangeable between the two CFM56 variants.