disassembly

So I bought a v-drive with a cracked Glenwood exhaust log with over the transom pipes. I have a set of Nicson exhaust logs that I can use but they have the through transom elbows on them and I can't get them to seperate from the main exhaust log. They've been together probably since 1972 when...

I know it was here somewhere can someone link or bump the steps to changing casale gears. thanks