20. Series 90, V16
Complex Says: In 1938, Cadillac released a new V16 as a successor to the legendary Series 452 V16. The upgraded V16 engine was significantly smoother than the outgoing engine and produced a healthy 185 horsepower. The combination of that high-powered (for 1938) engine and the incredible smoothness made the Series 90 V16 the fastest accellerating car in the world at the time.