google "27c256", thats what you need.
they'll come in PLCC and DIP package types. get the DIP package.
you can get this package in two type, ones that are OTP (one-time-programmable), or UV erasable. The erasable ones you'll need device for, or build a UV setup yourself, or even let the IC sit where it gets un-UV-filtered light for a couple weeks. i've used the UV cleaning thing on my electric toothbrush stand to erase one before, its just a UV bulb in there. took a few cycles for it to work, but it did.
in short: look for 27c256, DIP package, with a UV window if you want to reprogram them later.
or, 27c256, DIP package, OTP version if you don't plan on reprogramming them.