Greetings BBer's, I need some advice!! I recently had to replace the original y-pipe on my 91 744, where I discovered that a previous owner had apparently lost one of the 3 15mm flanged nuts for the y pipe/manifold studs, and had jammed on another nut that was close, but not quite the right thread... I removed the manifold to try to clean the threads, but the stud was shot. After the guy at NAPA blew up his computer trying to find a manifold stud for a 17-year old volvo (HA!), I got word from a local volvo shop that the manifold side of the stud was actually standard thread, so I just dug up a bolt w/ the same threads and put it all back together. The stud that was shot was the one closest to the block. Once assembled with new gasket (a fiber one, that I have since learned is crap-tastic from reading other posts) but I'm still getting a small leak towards the outside of the joint, away from the block and the replacement bolt! Is that gasket just that crappy, or should I try replacing all the studs with bolts (while shucking out for the quality gasket)? I had a devil of a time with the y-pipe to cat connection- both flanges and the studs had become one, and the nuts were so corroded their hexagonal shape had been completely lost. The cat-back was still solid, so armed with only a 2-spd craftsman dremel-type tool and some cutting wheels, I cut the studs inbetween the flanges which let me get the rear half of the y pipe off, then I notched into the cat flange on 2 sides of each stud head. The rest of the studs was easily knocked out w/ hammer and punch, leaving me 3 roughly U shaped notches. Once the new y pipe was attached to the manifold, I rustled up some hardware from the collection and used washers on the cat flange to pull the pipe snug with y pipe (and a new gasket there, too), tightened it up good and that side of the y pipe has been rock-solid for about 5 weeks so far, and that's on the crater-filled roads of NE Ohio... I hope that can help someone else out there who can't afford to replace the entire exhaust all at once!