Tripod heads - standardized sizes for mounting?
I picked up a Calumet cc401 4x5 monorail recently (my first foray into large format, so forgive the possibly foolish question). I was given a cheap aluminum tripod with a 3-way head several years ago, which holds the Calumet in its default portrait orientation just fine, but when I move the head to get a landscape view, the head can't hold it at 90 degrees - it just flops over as far as it will go (and it can't be tightened any further).
I was just given a Velbon Victory 450 tripod. It looks sturdy enough for the Calumet (at least as sturdy as my generic model), and is definitely newer than my other one, but it only has a 2-way head - so, I can't flip the Calumet. However, it does appear that the head comes off, exposing a bolt.
I know almost nothing about tripod heads - are they standardized (ex, should the head from 1 manufacturer fit on another manufacturer's body)? I can't find a definite answer - failing the above, do other Velbon heads fit on the Victory 450? It's a low-end model, and it was given to me, so it's not a big deal if they don't, but it would be nice :)