Larry I live in Canal Fulton Work in Cleveland and environs... I wish I had been in Boston when my daughters 87 244 " was doing this wonky crunchy thing " according to her friend. The repair, due to a prior agreement, was my responsibility..... ouch .... I am unsure of what the problem was or what was the repair I am very clear as to the cost of "dewonkying" an 87 244 is . If it is not to far out of the way perhaps I can give you a second opinion save you a couple of former presidents or better yet give a little peace of mind Otherwise depending on the friends understanding of exhaust, a cat problem is unlikely let me know if I can be of any help. I hope this helps.
Todd Cell 330 807 2173