That's not as old as some so it can't be called "antique". They aren't making the original chips anymore so you will have to find the part in a recycling facility. I don't think the AMD and Intel parts were pin-compatible, so you might have to find the datasheets to make sure.
This forum is "bar sport" so here is an approach that might be easier. Get a plug that fits into the socket and mount an Arduino on it. Put in some level shift chips and build a "Frankenstein-duino" computer in the original case. You get extra points if your sketch can use the floppy drive.