The gasket is fairly easy. You have to remove the mechanical advance unit by undoing the bolt in the middle and remove the complete points plate assembly. You will then find four cross point screws that will need an impact driver to undo. The casing will then pull off with a small amount of wiggling, get clearance on both valves on that side of the engine before you start.
You will need a new gasket, DO NOT USE ANT GASKET GOO UNLESS YOU WANT A SIEZED CAMSHAFT, and you should also change the seal.
The gasket surfaces need to be super clean before you re-assemble and you will have to gently lever the casing upwards to get it to go in.
It is permissible to coat the gasket with clean grease to get it to stay in possition for assembly.
Parts should still be available try
www.westernhillshonds.com