I think you would be mistaken. The car’s engines probably have more in common than the two planes’ engines (low-bypass turbofans in the original, vs. latest high-bypass on the newest ones; engines so different that they changed the plane’s handling enough to require the maligned MCAS). Avionics are entirely different and arguably much more vital to the planes function than a car’s instruments. The interiors are also basically not comparable (sure they have seats but that’s about it).