Whatever in the engine bay is back to where it belong. The old engine is a mess and the head too. In the end I just clean the transmission, put in new oil seals and just plug and play with the replacement engine. I did removed the carbon on the piston heads, valves and its surrounding areas though. The car has moved since been immobile for more than a year. The job is done but it is an old car so I need to look at other things that might need attention, mostly trimmings, brakes and the steering.
I now have an extra engine which I can rebuild and the transmission unit too. I can use it to power a DIY buggy if I have the raw materials, cutting, bending and welding equipment plus the will to do it.