Formula 1 teams in recent times have prefered to use the V8 engines, instead of the V6.
For example, Alfa Romeo is running a test with F2 drivers Tatiana Calderon and Juan Manuel Correa but are running with a V8 engine.
The use of V8 engines in an unofficial test is thought of as quite surprising as the idea of running a test is to see the potential of the young driver and should be put into a car with the same regulations as a current car.
Red Bull boss Christian Horner has in the past praised the V8 engines after being successful with this strategy in the past.
It's an interesting development which is sure to divide the opinion of people throughout the sport.
For the 2021 season, things will be complicated even more as 18-inch wheels will be introduced, which may result in the front runners being even stronger.