V8 engines are disappearing

[Carlos]

A cross plane V8 requires counterweights which means it revs slower and because of the counterweights the crank shaft is 'taller' raising the center of gravity of the engine, also makes it a bigger package, plus the crank weighs more, some say up to 20% more. Tall and revs slow but well balanced. The exhaust pulses are uneven which makes pulse resonance exhaust/tuning more complicated.Flat plane V8's have a second order vibration range, but this is minimized by a racing engines short stroke and light components, its higher in the rev range, and drivers are so highly paid they can stand a little discomfort.

Edited
Reading my post a second time - most of it is what checkered had to say.

[riff_raff]

The reason a planar (180 degree)4-pin crank is used in V8 racing engines is that it provides even exhaust intervals for each bank of cylinders, regardless of V angle. This provides for maximum effect with the acoustic tuning of the headers.

The flat plane V8 crank has primary force balance, but has a nasty secondary force imbalance. The same is true for an in-line 4. The result of this secondary force imbalance is the opposite ends of the crank wobble 180 degrees out of phase. The unbalance forces increase rapidly with increasing stroke length. So while these forces are manageable with a 50mm stroke racing engine, they are not acceptable with an 80mm stroke production auto engine. Production auto V8 engines use what is called a cruciform crank. It has 4 pins spaced 90 degrees apart, so it has very good balance, but the exhaust intervals of each cylinder bank are uneven.

The counterbalance masses required with a short stroke, flat plane V8 crank are also very small compared to a cruciform V8 crank, providing a significant weight savings and reduction in inertia of the rotating parts.