A couple years ago I had to HeliCoil the two rear holes in the head of my 22-RE for the exhaust manifold studs.I used the M10 x 1.25 (part #770-3020)HeliCoils. Well aparently they have finaly stripped out. What are my repair options? Can I go to the next size up safely? Any suggestions would be greatly appreciated. I'm wanting to get this done today (Sunday) so please reply a.s.a.p. if possible. Thanks in advance.