Once I had diagnosed it I set about removing the head, once I had removed the head I stripped it down and took it to the machine shop to be skimmed and pressure tested. It pressure tested fine and had .007 removed. I ordered up all the bits I needed, then set about cleaning up all the parts I removed. I cleaned up the block deck surface ready for going back together.
When I got the head back I lapped in the valves and then rebuilt the head. Once I had all the parts I put it all back together, ran and tested for a good hour and a half and it’s running as it should.
Some pics taking the head off.
Pics putting it back together
Short video of it running.