OK, I'm cautiously optimistic that I may have found the source of the problem. As stated above, the only constant feature through 3 sets of pushrods was the rocker arms. They are indeed Comp Cam roller tip 1.65 ratio, but they were supplied by the already suspect defunct machine shop. In comparing the Comp cam units to stock stamped steel OEM rockers, the pushrod makes contact with the body of the rocker at minimal movement (see photos). The cup for the pushrod ball is also way deeper and would hold the pushrod tighter causing the rocker end of the pushrod to break. Maybe these are not even Pontiac rockers? There are definite witness marks on every one of the rocker bodies where the pushrod would make contact through the valvetrain rotation. I just was not looking in that spot before. Whaddya think?
In photo 1 the OEM unit is on the left, showing the range of motion (rocking) before the pushrod contacts the body of the rocker.
Photos 2 and 3 further demonstrate my point, #2 is the OEM unit. See how far it can rock before contact occurs?
Photo 4 shows the witness marks from the pushrods.
Photo 5 shows the depth of the pushrod "cup" but more importantly shows how close the rocker body comes to the pushrod cup (left) compared to the OEM stamped steel unit.
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