Ouch. You may have a tough time getting a Helicoil in that size. Your best bet would be to actually call Mcmaster-Carr and see if they can track one down for you. I had a problem tracking down a goofy sized metric tap once and Mcmaster helped me out. Can I ask what you have that uses that thread?
Sorry for the delay… had to jb weld it instead. Replaced head gaskets on the wife’s car since the timing belt and pulleys were getting replaced. When taking out the egr tube, 40% of the threads inside the manifold side stripped. It was most definitely 19m X 1.5… leave it to Subaru to have such a unique part. We checked everywhere for that size helicoil and it appears to be non-existent.
Thanks though guys.