O.J. Simpson has an enormous head, apparently, and thinks that Cuba Gooding Jr.’s head is not big enough for Cuba to play him. Also, Simpson says Gooding Jr. is not tall enough. This is all according to former Nevada prison guard Jeffrey Felix — whose book Guarding the Juice is being published next month. Cuba clearly should have been getting his head expansions and leg extenders to prepare for the role, but he didn’t know it would be so much of an issue. Simpson’s yard name is “Bobble Head,” and the Native American inmates call him “Buffalo” … Because buffalo have big heads, you goof! Oh, but also, on a deeper level, according to “Page Six,” Simpson is “upset” that the FX series seems to suggest he’s guilty of murdering ex-wife Nicole Brown Simpson and her friend Ron Goldman. Oh! Okay. The head thing, but also this. Got it.