anyone know if to change the exhaust camshaft for a higher profile one in the rover vvc k-series head you would need to remove the head from the block?

Not unless you wanted to port it, or had to machine anything out of the head to make them fit.

cheers for that.

it is this
http://www.ptp-ltd.co.uk/shop/253_231/mg_rover/mg_zr__rover_25/performance_upgrades/vvc_exhaust_camshaft,_with_270_profile_by_piper_cams.htm
which doesnt require any mods to fit, except possibly offset dowels whatever they are?

theyre probably referring to the pin that locates on the cam sprocket.

You can usually put them in slightly different places to adjust the timing.