Exhaust issues

Had to replace the "Y" pipe and converter rot thru.  Found a direct replacement and brought to my local muffler expert.   when he called to have me pick up he tells me that he couldn't tighten the ports to the head as the studs were spinning when attempt to tighten. (one on each side)  When I get it home and do a closer inspection it looks as thought there is a spacer, or some type of fitting between the head and the exhaust flange, and the studs are in this part rather than the head itself.  I realize this is wordy but if this is the case it may be an easier fix than I first thought.  I'm not getting any help from my Chilton manual.  Any input is appreciated.

Thanx

Denem