Question on Transom Demo

[captsuperfly]

I have a 1974 SF that I'm redoing. It's an I/O I'm converting to outboard with bracket. I'm getting ready to demo the transom and had a question about what I'm going to find. I know on some boats with I/Os, the entire transom isn't cored... just a smaller area surrounding the outdrives. Is this the case with the Seacraft I/O transom, or is the entire transom cored - even in an I/O.

I'm going in through the inside skin.

thanks!