I have a 52 1/2 ton with a stock 216. The exhaust pipe donut has started leaking. I have unbolted the exhaust pipe from the header, but the old donut appears to be firmly attached to the exhaust pipe (which is in good shape, so I don't want to bugger it up). What is the best way to remove the old donut with out messing up the exhaust pipe? It's kind of hard to get to, so I'm thinking of taking the exhaust pipe off at the muffler.

My dad always told me, "Don't force it, get a bigger hammer".