Helicoil

[Ronin]

A stud hole on my exhaust manifold has been helicoiled, badly as the oil gallery had been holed and it leaked oil and it never stayed tight. Today I noticed loads of smoke coming from under the bonnet had a look and and the stud was was hanging out with the helicoil on the stud. What I want to know is will it be possible to redo the helicoil and if so what thread do I need ect.