The walls are all beefy enough to helicoil them all, however, the PITA will be helicoiling the right/driver's side bottom holes. All the 10mm holes are blind (ie don't protrude through oil/coolant passages as do the fore and aft bolts on the uppen intake manifold). Most of the 8mm holes (forward of the timing chain) are thru holes and the chips can easily become FOD. I HAD to helicoil a couple of those holes and to do them I soaked a couple of paper towels in oil and stuffed them behind where I was drilling and tapping. It seemed to work. I'd look at it as a cost/benefit analysis. If the Al threads are good enough why drill them out oversize re-tap and helicoil insert if you don't have to. Besides, its a lot of taping up and alot of FOD potential. By helicoiling the threads, do you make them stronger? Absolutly. However, My opinion is if it ain't broke don't fix it.

Again, my advice is to test each of the threads and if the bolt goes in a reasonable length of travel then don't mess with it.

Either way, best of luck!


Scott