From the perspective of doing this DIY, you can JUST make it work financially IF you are keeping the car. Rebuilding the original head is a mugs game, it will not last unless you can have it Hot Isostatic Pressure impregnated after the refacing. This is a micro thin coating that prevents (sort of) porous surface seal failure and so the only sensible method is to fit a new head, AMC make some good parts and there are some Chinnese copies around that seem OK. A new cam kit is also very sensible, make sure it is billet not cast. Alternatively, the sooner all light vehicle diesel is scrapped the better my lungs will be.....