I would not recommend the FAST EFI.
I have installed the FiTEch with good luck, but would lean towards the Holley Sniper just for the customer support aspect. The big win of the Fitech is the fuel command center. It is a simple solution for a simple problem that trips up a lot of people.
Last, do you have the 340? The more I read these posts, I recommend the modern Magnum family over paying $3-4000 for an ok 340 that will still need something. I think the common 360 380hp crate engine is about $5000.
