Well a simple old bolt has just caused me to ruin my exhaust manifold so now everything has to come out and a new (used) one will have to go in, I'm use to this kind of stuff by now. Nothing ever goes as planned. If anyone has one lying around I could sure use it. I have a 71' Fj-40, 1F engine all stock. It crossed my mind that while I rip everything out I should replace the manifold with headers, any thoughts on this, will I gain anything by doing this? Thanks. J