Keeps stopping 740

I had a the head gasket changed today.
The garage is now closed for the day.
The car will not tick over and if the engine stops its almost impossible to
restart.
Any ideas.

 

It sounds like the timing belt was put back on with the cam one tooth
retarded. Doing that also normally produces a hollow exhaust note.

The good news - the engine is non-interference (assuming it isn't a
multi-valve engine - most 740 engines aren't) so there won't be any damage.
But the engine will behave like that until the timing belt is put back on
right. More good news, for you and the mechanic - it isn't a difficult job.
The mechanic should have you fixed up in half an hour or so.

Mike