Double-checked....it's on tight, must have just been sitting there loosely for pic, or didn't have coolant added at time. Took it half off a did up again, those ears certainly help!
Firebird NOS RC27 radiator cap closed lined-up with tube (7) by
Ben, on Flickr
Firebird NOS RC27 radiator cap closed lined-up with tube (6) by
Ben, on Flickr