I believe the valve cover stud is threaded M7( x1) on the side that screws into the head and M6 on the top that bolts to the valve cover nuts - hence 7/6 in part description. Please check me on this.

If this is correct, I believe you will need an M7 x1 helicoil kit of an appropriate length - 25mm

Helicoils will probably work fine in this application, but I prefer time-serts over helicoils as I believe they are stronger inserts and better able to handle multiple in/out of the threaded bolt - although hopefully once you get the stud in, it won't need to come out.

Price out both time-sert and helicoil m7 kits. If there is a big $ difference go with the cheaper one.