The Lancia V6 in 1950 used a 60° angle between the cylinder banks and a six-throw crankshaft, to achieve equally spaced firing intervals of 120°. This still has some balance and secondary vibration problems. The first Buick V6 was a 90°, based on their 90° V8. This produced a rough-running design. This was unacceptable to many customers. Later designs have improved the engine and made it reasonably smooth.