Does anyone have any experience with threaded inserts in this situation and what depth did you install them to? can anyone foresee any issues having the insert threaded in just below the mating surface for the head/jug? my master mechanic friend didn't seem to think it was a big deal, but, i wanted to use the OE bolts so i installed the insert at a depth the same as the other threads. however, that bolt is stretching and there are some other issues so this is just what was crossing my mind, any help would be great thanks. so.. i don't have the engineering data but i'm sure there is some reason the threads start so far down into the jug, however.. maybe not. All i can think/figure is that the farther up the point of attachment is, the higher levels of heat the threads would be subjected to as it gets closer to the actual point of ignition and i'm sure the metal 'moves' a little bit more in that area as well. Also, having the threads further down it would end up pulling on a greater amount of material vs if the threads started immediately at the top of the jug. Now, with a threaded insert i'm not sure if that really matters.