Helicoiled exhaust header bolts

[Highbanked Hauler]

  ALL of the exhaust manifold bolt holes in one head have helicoils put in but in one hole the first quarter inch there is no thread for it to screw into. Other than catching the last half inch of threads with a 7/16 bolt can a machine shop do anything to rebuild the threads. I really don't want to toss the head at this stage of the game.

[c00nhunterjoe]

Drill larger and install a threadsert. Will be difficult to seal for coolant.