block filler

I was reading about using a block filler for my 350 block (will be a 383) as it strengthins the block. I read its good to do on a street engine up to the freeze plugs and it can add a minimal amount of HP. I asked a couple people about it and they didn't seem to know too much concerning it.

Does anyone have experience with it?(probably a dumb question)

Does it really do much to help or hinder?