Catch of the day.
I've found a Head Honcho. It's an original one, from a Saab dealer clearing out his shop.
He had it for the Saab 99, fitted with the 1700cc version of the Triumph slant-four.
When I was restoring my car I couldn't get the head off to check the cylinders. The engine was running fine, so I didn't put to much effort in it and left it as it was. The engine is still fine, but knowing the problems with stuck heads I couldn't resist taking this tool home.
One bolt is missing, so I'll have to find a new one. It's 18.8mm and spanner size 1 1/8 what thread would that be? 3/4 UNF ?