Garrison's connector piece is a snug fit for all the Headmaster bodies as BIG as Fortress Maximus, as tiny as Nightbeat.
With Headmasters all the ports are universal.
If you watch my Garrison video, it was a snug ass fit for me too.
http://www.youtube.com/watch?v=jKTJ3zv-LqY
Around the 6 minute mark, but then again my Hosehead body was super minty.