'good brain' is not a correct and usable phrase in written English.
It can, however, be used in spoken English. For example, one might say, "I'm feeling pretty good today - my brain is functioning well!".
"I'm speaking with myself, number one, because I have a very good brain," he has said.
Anyone out of college, if you're not looking at Larry, you don't have a good brain".
I'd never heard it before but I believed it: I had a good brain.
You've got a good brain, and you've got a big mouth — use it".
"He's got a good brain on him, and he's very talented".
Trump's self-described "very good brain" shows no signs of learning from his past stumbles with women voters.
But who would dispute Sugar Boy's father's larger goal for his son: "a good brain in a good body"?
My father's mother had lost her husband rather early, she was a widow with five children and had a good brain too, so it was OK.
He had a very good brain, but he was probably upset that he worked like a slave but was not an owner . . .
He's got a very good brain - better than Blair's - and a very good sense of direction, which I think Blair didn't really have.
