C2 SST 27SF512 Chip

These assemblies support the full 64k memory space, and are genuine Greenliant/GLS27SF512. These work great with the G1, Honda, etc. This is the max size for a 28-pin chip. When the JWT or other chip isn't big enough, such as later-model TBI GM systems, this chip will do the trick, a 70ns flash drop-in replacement for up to 27C512 EPROMs. Make sure your programmer supports it, there's a funky programming erase voltage required (BURN2 APU1, or PocketProgrammer2 should be fine). Works fine with 1227165, 1227730, and other similar ECMs. If your car normally takes a 27C128, 27C256, or 27C512, these should work for you. Just adjust the 'Start of Device' value when programming. (For 27C128 original, set to C000 hex. For 27C256 original, set to 8000 hex.).

Note: if you only need 32k or less memory, you can use the JWT SST27SF512 chip instead. 
Note 2: The pins are pretty fragile, so be careful. They are also too thick for use with an S4/low-profile ZIF.