Copper head gasket chunks welded in place. Need advice

I took the head off my 2a last weekend, and the head gasket was blown (as suspected). Missing a big chunk between cylinders 2 and 3. Most of the gasket came off quick and easy, but the section that blew out is fused to the head and block. I was able to get the the head clean. It took 3 hours of scraping and brushing with a razor and brass brush. Brake cleaner and degreaser aided in this effort.

There is still a nasty chunk left on the block, and I am extremely hesitant to use anything that might make its way into the block. I have soaked the section in penetrating oil and worked a razor against it for about 45 minutes with zero progress. I have found a lot of conflicting information online, and would rather tap into the collective knowledge of the folks that actually work on these trucks.... soooo any one have a method to get this chunk of metal off my block? Am I being too cautious? Thanks in advance.

I soaked the gasket chunk in PB blaster overnight, and hit it with a brand new gasket scraper this afternoon. It came off with about 10 minutes of elbow grease.