I started to take off the end cap/exhaust elbow on my 1971 Lehman in a 42 Classic. Flange on my engine is square. The exhaust pipe curves outboard with a large flange at the end which coulples to another length of pipe which goes into the muffler. I should have taken a picture.
I was able to loosen the two top bolts without trouble as well as the bottom left/outboard. The problem is the bolt at the bottom right. I can get a wrench on the bolt head ,which is slightly rounded from someone else's attempts ,but can't get enough leverage to break it loose. I tried heating around the bolt as well as hitting it with a sock extension without success.
At this point unless someone has a neat fix, I will try and weld a long bolt to it. If that doesn't work, I will cut off the exhaust pipe with a sawzall. After 20 years it probably needs replacing.
And why am I doing this. Becauase the engine started steaming exhaust. Checked there seemed to be good water flow. Months later Then engine overheated badly. Checked hoses, intercoolers, sea strainer and raw water pump. All fine.
Looking for advice.