The crossflow head was installed with some old gaskets and even though the the tap ran true the torque would not hold in two holes. So inserts (M11) to be installed .
"the torque would not hold in two holes" ? Dave,
If you've found the thread in the block to be M11 x 1.5 and not M12 x 1.5, I'm going to be surprised, not to mention soundly educated! . . and I'll need to apologise, too.
You are then fully authorised to get that penguin .gif and smack me upside the head.
Seriously though, I'd love to be educated.
Did you drill that hole in a piece of steel or ally and thread it with your M11 tap?
Does a head bolt thread into it?
P.S. The hollow dowel in the block looks to be beaten up a little.