I'm still having the same problem and I have checked the heatshield. If I lift the head then the chest armor fits just fine, but the head is tilting back. When I put the head in the right position the chest armor does not fit. Can you guys point to photos maybe? That would be helpful. Thanks!
The first pic shows how the armor fits with the head in the correct position and the second pic shows how it fits with the head out of place.