F.A.S.T. Ez EFI
Car Craft just did a test where they put it on a sb and ran some dyno pulls then swapped it onto a bb and did the same thing. In both cases the systems self tuning had the power to within a hp of the carb'd base lines. They then did a road test on a sb El Camino and went from 13 mpg carb'd to 18 mpg with the system.
Seems like a great way to get into efi without need to tune the system. It is kind of pricey though with a complete system about $2500.