I've never bent pushrods, but I did have some valve sticking problems. My '59 F-350 had sat for about 10 years, with a nearly full tank of gas. When I first got it going, it ran like a swiss watch. But after it sat for a week or so, the next time I started it, it missed, and ran like crap. Turned out, my valve had stuck open. This happened a couple times, before I finally replaced the tank. The old one had so much gunk in it, it never would have come clean.