MANFROTTO Tripods: heads interchangeable?

I have a MANFROTTO Compact Advanced Tripod, and am thinking of changing the head, tripod itself is fine but have a few niggles with the head.
Are all manfrotto heads interchangeable?

I think they are all 3/8" female thread, so I would say, yes.

"Almost all of" the Manfrotto line sticks are compatible with their tripod heads. Could it be something in the head such as the screws and/or allen bolt/nuts?

I prefer the Gitzo series three carbon fiber, yet most of the higher end Manfrottos are also equally as impressive. Just be extra cautious of weight ratings, which are not quite standardized or tested well enough, and also be sure to routinely check and tighten connection points for Manfrottos

Thanks for the advice guys.
It is an issue with fittings, am looking for a head that offers easier maneuverability, I dropped my K3 from the tripod when trying to adjust the level, both tightening bolts were too close together.
Just lucky I was setting up and always keep the camera strap around my neck until absolutely ready to go...

I can recommend this head. I have used mine for years. Not the lightest head you will ever come across. But because of that easily supports long lenses. The panning lever is really handy when doing landscapes.

http://www.amazon.co.uk/Manfrotto-Midi-Ball-Head-RC2/dp/B002PWHOYG/ref=sr_1_1?ie...

Looks good, will most likely give this a try, looks much more stable and secure than the one I have.

I'm not getting a clear picture of the problem, exactly. Could you be more specific?

I would suggest that the head is fixed, i.e Non Removable

I've only been able to look at an image HERE

Given that the price is £84.95 inc vat and generally you'd pay that and more just for a Manfrotto set of Legs with a head starting at £50+

Manfrotto make this tripod with one of two heads, so they appear to be removable, but may be designed especially to fit the (apparently) smaller diameter top of the centre column.