This guy on eBay has had the gasket listed that you need. I see none currently listed but you can probably contact him to get one.
http://cgi.ebay.com/ebaymotors/Mopa...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
If the link don't work it was item # 390087263510
I went through the same problem a couple of years ago when I replaced a cracked manifold on a 72 Swinger. Make sure the cup has a perfectly flat seal and don't use anything other than the gasket.
You might want to get that stud out if you can because you need to get it good and tight so it will probably strip like mine did. I got mine out, cleaned the threads good and used nice SS bolts and it sealed perfect.
When I did mine I had access to a couple of manifolds and I wish I would have put the earlier style because it would have saved a lot of down time and cussing.
BTW, the later manifold won't work because it takes the electric assist choke and that is why the side is open, it also has the linkage rod end pointing the opposite direction so you can't just switch them. Always keeping us on our toes, the guys at Mopar never figured we'd be swapping parts 37 years later so they didn't plan for this stuff to work across all years.
