What did GM use to fix cylinder porosity. I just finished a tear down on a
5.7 truck engine. In the #3 cylinder there is a spot avout the size of a pencil eraser. It has been filled in with something. I dug it out and it seems to be something like JB Weld. I decided it wasn't a block that I would use since it would need to go about .040 overbore to be useable. I sandblasted about 15 minuites and finally got all the filler out. It is obviously a void, not really porosity but just a casting defect. I know the engine has never been down, I personally know the man who bought the truck new and wore it out. Its clear that whatever was used works. The engine was at 187XXX miles and the filler wore just like the rest of the cyl. What do they use, where can I buy some/