Here is my jointed Red Vulture custom, same body parts as my custom Shadows but with a removeable repro gas mask trooper helmet and custom decals on the helmet / body...
Just realised I forgot to screw the torso up before taking the pics...
Im sure its possible to hollow out an original, mine was a repro one and slightly larger than the original and already hollowed out... I had to dremel it out some more but even then very few heads would fit...
I got this one off ebay along with some other helmets (hiss driver / wet syut / eel / techno viper) I think it is the same guy or they know each other as he has the removeable techno viper helmet up (though the quality doesnt look as good).
Usiong the removeable techno viper helmet for my Red Wolf as my present custom already uses that head...