Oil Leak

I cant seem to get a break on my engine. It just keeps giving me fits. The latest is I have an oil leak around the base of the distributor where the dizzy drops into the block. There is a chunk of metal missing from the area in the picture i have attached where the metal is gone and I am losing oil from this spot. I have tried replacing the O Ring gasket and the dizzy base gasket without success. I tried some Permatex great stuff around the dizzy and it did not leak at idle but leaks when a load is put on the engine. I am going to try some JB Weld and try to build back up the area and see if I can get it to seal. Anyone out here have any suggestions? Short of having the block welded, I am at my end with this. This picture is from the web and is for reference only.