There are people that drill out the sides of old cases using circular saws and install larger fans. But if you don't care as much about the noise, there are more powerful fans available for most fan sizes.
I don't know that the largest of video cards would even fit in something like this though. They're too long. At least not without cutting. My case BARELY fits my graphics card and it's a lot newer than this.
Modern graphics cards are designed for cases without optical drives and the hard drive cages below them.
Could just install a small modern mobo tho and use it for a retro inspired internet surfing machine.
I really want one of tho old clear blue or purple cases that were inspired by the iMacs back in the day.