The 4.9L ECM uses what is known as a Memcal unit. The chip is permanently soldered into this unit. You can purchase a plug in Memcal adapter from Craig Moates that will allow you to easily remove and replace the chip. Some programmers try to erase and re-program the chip while it is in the Memcal unit and this can work, but IMO reprogramming 20+ yr old electronic chips is not a good idea. When I program I always use fresh brand new chips. The 4.9L uses a generic 27C512 eprom and its still available as is the flash based memory version with the same configuration as 27FS512. The electronically erasable memory is faster and easier to work with. .
[This message has been edited by Dennis LaGrua (edited 09-23-2015).]
