K301A Exhaust issue
 

The previous owner of my CC129 welded the exhaust elbow's tightening ring directly to the engine block. There's a visible gap between the end of the exhaust pipe and the block, exposing the inside of the cylinder. It's hard to tell through the carbon buildup if the threads in the block are still intact. My father-in-law, who works on military ships, has a large enough tap to clean them if they exist. However, I suspect if he welded it the threads are toast. The engine runs great, but it's loud, and I'm worried about moisture, dirt, and insects getting into the engine. I really dont want to rebuild a motor with a new block with it running so well.

My plan is to carefully cut the welds and clean the mating surface with a file to see if any threads remain. If not, I'm considering to have a welder add a threaded flange, perhaps using a large Heli-Coil. I'm open to any suggestions from someone with more experience than myself. Thanks in advance!