How did this happen to my pushrods?
Just wanted to post a follow up here... I am very doubtful that the pushrods have twisted. I tried to post as good a close up photo as I could but it still doesn't show quite enough detail I think. The pushrods are actually scored with the spiral pattern, as best I can tell those are actually scratches in the surface of the pushrod. I couldn't think of any way for them to get scratched up in that pattern, but one poster in this thread mentioned that it was probably the tooling used to roll the pushrod when it was assembled. I think that's probably the most likely cause. I'm also glad that others have seen pushrods just like this, I'm thinking now that I probably don't need to worry about them.
My cam has a moderate amount of lift but I don't think that it's enough to cause coil binding on the springs. Also, the springs are very tired and old, so weak in fact that I can spin some of the springs by hand. Very doubtful that there's enough spring pressure there to put undue stress on the pushrods. FYI, new springs are on the way and I can't wait to get them in and see if they eliminate my high rpm misfire.
Thanks for all the replies