There are only three chips, the 450 chip, the 550 chip, and a chip that afaik was made by Buschur (can somebody confirm this?) the 660 chip. The best you could do would be to use that, then make final adjustments using whatever adjustment capability you have with the gcc. I don't know if it's enough, I've never even seen one in person. Another option would be getting a chip burned to take up some of the injector compensation slack, enough to make up for the difference between 740's and a 550/660 chip. You could talk to Jeff O. at dsmchips.com and see what he thinks.