I'm suspecting that my RST cylinder head has a crack somewhere because I keep hearing bubbles of water after I switch off the engine until it cools down, even though I've got the swirl pot.... which means compression is leaking from somewhere.

I found a 1.9 CVH (USA) modified cylinder head for a bargain. Is this the same as the 1.6 CVH head? If not what differences does it have? Thanks