Hi- figured this out about 2 hours ago and think it looks pretty good, all you have to do is put a neo shifter head upside down in the gap in the back of galvatrons chest, no glue, it is held in by his back kibble (make sure the blue peice connecting the cab to the back of the robot is horizontal) the light is tuned on by folding the lower part of the cab so that it is putting pressure on the switch (the legs have to be bent straight down and facing forwards, otherwise the switch will only work if you push the lower part of the cab)

Now you try!

 

That confirms it, Galvatron is just Bays Gypsy Dangers.

 

What it should look like from the side

Here's an image of what it should look like from the side

 

Cool!

 

Nice. Looks really good with that light up core.

 

I'm definitely planning on adding an LED to my Galvatron. A big hole in his chest with lots of room for the batter and switch in his cab... it's a given!