If you have time, you can check it out yourself. If you search in here, you can see pics of what to look for (I'd do it for you, but it's painful to do so on dial-up).
Look for a wobbling balancer, the timing marks to be way off if you try to check timing, and the outer ring to act as if someone hit the face of it with a hammer. Also check for cracks in the elastomer (rubber) between the two rings. It tends to crack and bunch-out as the ring slips.
If it is the balancer: New balancers range from 80-300 bucks (for most). A non SFI Pioneer can be had from some parts stores for 80 bucks or a bit more and is a good unit for a street car IMHO. The SFI Pioneer is about double the price. A lot of guys like the PP units, while a few dont.
Romac makes a very nice piece, but it's pricey and might be overkill (dont know your combo). A search can reveal tons more opinions and options.
You can rent a puller and install tool when you swap the balancer (it's one tool kit). The fan and rad will probably have to come out. The rest is R/R.
Good luck.
