Cut a washer of the correct thickness in half and tack weld it to the original to make up the height difference.
I figured a bit of difference was design but everything tight and the header is flopping around like a fish out of water.
I bought them used I don't remember they have no name on them.
The top link to the slant . org article. Do you know what book that picture and info are from ? I would like to see more pages.I used this info to install mine and glad I had it, read it well..tighten ALL by hand and when you have it set correctly start from the center and go to 10 inch lbs !!
http://www.slantsix.org/articles/supersix/instructions.jpg
Gasket.. = .. http://www.gprsmopars.com/shopping/start.php?browse=1&cat=6&=SID
And here is what you are going threw and how to get it dun
http://www.slantsix.org/forum/viewtopic.php?t=14621&view=next&sid=e8ad20b416486491be02defa61142bf0