I was going to say that $6 sounds really cheap but $60 sounds way too high. $30-40 is what I paid for the gaskets and orings. I don't know if you can use common trade orings. The best way to do that would be to get some old ones from somebody and take them to a CAT dealer who usually stocks a ton of orings, by size though. I didn't do much to clean out my bundle, I sprayed it out thoroughly with fresh water and ran some biodiesel through it. I cleaned all the crud off it and had it pressed back together.
Last time I bought the things the ford dealer wanted $90 for the orings, $17 for the gaskets. I got the Orings from the International dealer for about $70 after tax but the header gaskets are different and had to get the gaskets from ford for $17 , This is why I mentioned the felpro gasket set being cheaper, And you get a few spare goodies. Since that time though a bunch of places are carrying the felpro header gaskets for $5-7.
I've got a set of new ones down there I suppose I could try to measure and get a number on the things, probably not tonight though, I'm beat.
-------Robert