Originally Posted by fielderLS3
A V6 is inherently rougher than a V8 all other things the same, pushrod or not. In a V6 luxury car, they just put more into things like engine mounts to insulate the rest of the car from the engine. The engine isn't necessarily smoother, the vibration just doesn't get transmitted as much.
Yes, it is inherently hard to balance a 60* V6 than a 90* V8. Luxury car companies just puts a lot of money into reducing the vibrations...money GM is just starting to invest. It will always be more expensive to get the V6 to run as smoothly as the V8, push-rod or not. With new technologies for block casting, piston/rod production, we are seeing some of that cost offset in other areas when there are fewer cylinders. I-6 engines, however, do balance very easily.