I have a 1980 bronco with 351m. The engine keeps bending pushrods. Before some of the valves got stuck in the guides, but now it seems to be bending pushrods while the valves are still free. The truck had bent pushrods when i got it as well. Is this common for the M motor? Also found bent pushrods at the junkyard when I went to get replacements for mine. Any one ever heard of this? thanks

 

Jumped timing or seized rocker arms have the potential to do the same thing. Oiling problems in the top of the engine would affect both valve guides and rockers.