Adam, 22, was on his way home from the city when he stopped at the Melton Highway restaurant with two friends on August 16 at 3.30am.

He was outside having a cigarette when a man in his early 20s, who appeared to be drunk, approached Adam's car and tried to get in the back.

"He went to open the door and I said 'Buddy, what are you doing? This is my car. You can't just jump in the back seat'," Adam said.

Moments later, three friends of the man pulled up next to the car, got out and started punching Adam, who was hit in the face, picked up and thrown to the ground.

One of the attackers was armed with a pole, which he used to hit Adam over the head.

Adam was also stabbed in the wrist as he tried to return to his car.

His friends took him to Sunshine Hospital where he spent four days and underwent surgery.

Adam said a woman friend with him at the time was also hit several times in the head.

Detective Senior Constable Leigh Wheatley, of Keilor Downs, said the same four men had also caused a substantial amount of damage to another car waiting at the drive-through a short time after Adam was assaulted.

Adam, a sub-contractor, said it would take time for him to move on mentally and physically.

"I can't describe the mental scar," he said.

"I've been in this area for a long time and I've felt free to hang around at night, but what happened to me has changed my point of view.

"I don't think I'll be going out much at all late at night - there's too many warnings now."

Keilor Downs police want witnesses to call 9365 3348.

The men they want to speak to were aged in their early to mid-20s. One was described as Caucasian, while the others were described as of Maori appearance. The car they were in was a grey/light blue Ford.