Quoting OldHairyBastard:
Dave,
Can't you just tap the holes to a bigger size instead of using coils? I re-tapped all of mine and used standard studs as they are easy and cheaper to find. On the 2 outer big studs I bought studs that were bigger going in and smaller out so they would still fit thru the holes.
The reason I didn't do this was because I couldn't find grade 11 bolts in the correct length, thread pitch, and that were flanged. One size bigger wouldn't of been enough, probably would of at least had to of gone 2 sizes bigger. Which would of probably required my fp manifold to have the holes enlarged as well. Time serts were a much better solution.