I have seen only one engine with bent pushrods (2), different cylinders,
different valve (exhaust and intake).

So, both head were in good condition, a working engine with no real problem,
well, both head gasket were leaking, but thats normal, nothing wrong here
:-))))))

So, that said, that can happen for no real or obvious reasons! i cahange
both rods, did a re-seal and the guy went THE NEXT day for a 6000 miles
trip, came back and everything is fine... so!!!

Cheers, Ben
http://www.benplace.com/vw2.htm