i have a zvh 2.1 efi built by ian howell before i owned the car but it has a few oil leaks now and possibly needs a new head gasket as when left on tick over it heaves (revs up and down) also the top breather pipe keeps getting clogged with what i can only describe as lemon curd type gunk i have a bailey oil seperator tank and the waste pipe which is under the car from this when running/hot smokes quite a bit but none out of exhaust so im thinking it must be the head gasket how hard would it be to change all gaskets myself including cam belt oil/water pump whilst the gaskets are been done i have all the tools i need i think unless there is anything special needed how hard is this to do or am i better of paying through the nose to get it done at a garage