This took a bit more work than it may look.
It was a junker CW Brawl missing its head, neckplate and weapon, and its chest had cracked, I think because the spring in the combiner peg was too strong.
So I pulled it apart and cut the spring in half. A classics deluxe Megatron handgun fit perfectly as the weapon. I found a neckplate in my parts box - I think it was from a movie deluxe Brawl - then put a FoC Vortex head on.