If you want to pump it up (cam etc) and tune it, I don't know why you want a factory system. Holley HP you can buy what you want, you don't HAVE to buy the entire system. Do your research. You will have to sub some of the components for "GM style" components such as temp senders, and will have to buy a wideband sender (not a complete wideband with gauge) that matches the Holley.
There are other ways to fly. Megasquirt, and I don't know what all