Where are you located? Dale (Volvo245GTI) has just pulled a good working LSD off of a 123GT (gear ratio would be 4.10). I've just about got my 3.73 ready to install, but it is a 1030 out of a 240 not a Dana 27 from a 122 and that's a conversion you have to think once or twice about first. I doubt there will be much of a difference in performace and drivability (I also have an M41 that is going into this car - they aren't all that hard to find) and a 9% change in gear at the rear end isn't going to change all that much.

As far as I know the Dana 27 still has parts available - Don't tell people you're looking for a Volvo and the parts are easy to find with a little effort. As for Vintage Performance, I wouldn't be buying anything from John Parker - have a look in the archives. He's pretty good at the e-mails until he gets the cheque. Ask how I know.