What type are these planes that are flying in formation near Culver City, CA?
My (current) guess is that it may be a 

Nanchang CJ-6


  The Nanchang CJ-6 is an aircraft designed and built in China for use
  by the People's Liberation Army Air Force (PLAAF) as a basic trainer.



Round nose.
Sufficient number airworthy. 
Rectangular wing shape.
Main gear folds inwards and the nosegear backwards which seems to fit when I zoom in your pictures.




and they do airshows:

(source: riversideca.gov)  

Coincidentally, the upper-left aircraft #43 also appears in your pictures (first picture, rightmost aircraft). Another below of her below:



update: as Cardinal said above, "This is likely Tiger Squadron, perhaps flying for the Israel Independence Day Festival over Rancho Park in mid May, as detailed on their Facebook page."