Since this is so old, I hope that you got your measurement. I have a realted question that I htought this group might be able to help with. My rod is in (73 Barracuda with a single rod) and working, but rattles like the devil! Anyplace in particular that I should start looking? It really only happens while driving and I don't want to lie in the trunk with the wife driving. Also, there is a small metal tab in the center that my rod is running through - is it supposed to? I'll get some pictures tonight, but just wondering what others have. The body and chassis books don't show anything and no one posted a pic of the center section. Thanks