At least with LN3s, a bad harmonic balancer will have big tears in the rubber

Time to dig this video out again...This is a bad harmonic balancer on a LN3.

http://members.shaw.ca/bonneville01/MVI_0003.avi

Physically the HB on my '89 was shredded on the inside rubber portion all around the diameter of the outer and inner part of the balancer.

Both of mine looked exactly like that.

Update - I've done more reading and I agree with the thoughts expressed that the problem is most likely the coupler. However I plan on going to my parents this weekend and checking that the HB is in good shape before ordering parts. From searching other posts it seems the best way to tell if the harmonic balancer is bad is to remove the built and try turning the outside back and forth, if its bad the outside will turn more than the inside.

I also found this write up on replacing the coupler that will come in very handy: http://www.cardomain.com/ride/479367/2
(thanks Kenneth).

I got the impression from reading other threads that I should replace the lower intake gaskets while I had the super charger removed. I then saw a few posts about how the lower intake gasket failure is mostly a Series II problem and not a common problem with the series I.

Should I change the lower intake gaskets?

Anybody have the part number for the GM metal bypass fitting?