Yes something like that, we did cut it with a grinder...the very specialist way..
The holes in the block we enlarged with a sandpaper roll on the drill.

We have to work with what we have

Looking at the crank today. The broken flywheel bolts are going to be a pain.

If I recall, the person who gave it to me said, the bolts he was supplied with, were to long, and they nipped up on the back of the hole, before clamping the flywheel. So it looked ok, but sheered when he started the engine. They are in there tight.

He made an attempt to drill them out, but couldn't make much of an impression on the high tensile steel.

The hole is about 8.2mm. I have an 8mm cobalt drill that may do it. I'll drill down just enough to center a hole so I can then drill further down with a smaller drill. Then use an extractor. The tricky bit will be holding the crank still.

The crank big and small ends appear in very good condition. So I think it's worth the effort to save it.

I've struggled to make progress on the crank. Think I will take it to my local car engineer tomorrow. I'm sure they have extracted thousands of broken studs over the years.

So, that didn't go so well! They declined the job as the metal is so hard.

So went out to the peeps who did the crank cases. They are also dubious of the high tensile steel, but will see what they can do. I think the old boy engineer there, sees it as a challenge. There was a gleam in his eye, when he realised he would have the get the heavy equipment out.

I have the crankcases back. Now I need to do some serious cleaning.

Instead of heavy equipment if you have a steady hand you can try to weld a fat welding rod to the stud and try to turn it with that.???

Good idea, but unfortunately, all the bolts are broken below the casing level.

Can be removed by “spark erosion”. EDM.

Thanks Pete, I'll let them have the headache

The crank cases are not quite right!

Either barrel will just fit in one side (as it should), but neither will fit all the way in, in the other. So it's not quite machined out enough. To be fair to them, they knew I was keen to get it back, and fitted it in between other jobs. So possibly rushed it a little. It was intially thought it was snagging because it was dirty, but turns out not so.

I'll take it back when I hear about the crank.

Edit
I'll spend some time today cleaning the crank case up

I've cleaned up some, but it's very boring

So, I'm thinking something like this, but need to increase the height and diameter just a little. Probable a 1/2 or 3/4 of a mm

Or should I go for the full 'spectical' look?