Update, but first rant:
I'm not solely blaming the FiTech system for the trucks issues, but I am most totally saying that from the exposure that I've had to it...the available documentation, the "help" from the mfg, and its inconsistency to function as all the resources tell me it should...it would never be something I would spend money on, nor install on my own vehicle. Not when I've had success with other comparable EFI systems, and not when used to the function of "real" fuel injection. I'm glad its worked for those of you that it has, maybe this one is just crap. I have more related to why in my update below.
/rant
Update: So after verifying all the stuff in the last post (firing order, condition of all ign component, timing mark location in reference to actual TDC and cap/rotor)...we had a mostly running car. There were no vacuum leaks I could detect, and according to the screen, the engine is pulling like -16hg at idle as a reference. Found the factory adjustments for the throttle screws and reset them (passenger side is NOT iac screw, according to the guide). Fully re flashed the "ECM" to its factory V8 config, and re did the setup AGAIN.
Didn't want to catch after the flash. Got it to catch and idle again with some pedal input. Consulted guide for cranking and start enrichment, made two small tweaks in line with suggestions. Felt better when cranking and caught quicker, still idled like dogsh!t.
Did the IAC calibration/adjustment process, but again ran into the limitations of their guides. At no point does it allow the IAC screw to be dialed back far enough to get the IAC count within spec, but also keep the motor running. With the TPS% setup and checked the way they wanted, the truck started with a 200 IAC count. I can only manage to get it as low as 82 and keep an 850-ish idle. It still feels like its hunting, and any less IAC adjustment and it will instantly die. I had some luck on forum threads with things to try, haven't gotten through it all yet. Some of the info conflicts itself.
Its also during this time that the FITech just decided to stop commanding the fans. Awesome. Checked and tested all the wires, fuses, relay. I can manually energize the relay and get fan control. Checked all the Fan settings in FiTech, and made sure all the commands and on/off points were correct. Still nothing. Put a meter on the signal wire coming off the FITech unit and forced it to fan state ON, but it didn't appear to have any sign of a signal. Had to put the fans on a switch for testing so she wouldn't melt herself down. Also had the FITech screen whitescreen out on me once as well. Yay.
Mike, install yours and tell me whats wrong with mine. Or give me some hope and tell me that its perfect and I just have a bad one.
With the thing timed, mostly new ignition stuff which all outwardly seems to be working, no leaks of any sort, and no other signs of clear mechanical defect...I do not know what to blame besides the only component that I don't really have control over...fuel. Otherwise I need oddball suggestions, because "normal" stuff isn't fitting the bill. I may not be builder-of-the-year, but for f*cks sake I've built enough power on dumb setups that didn't require this level of head scratching. Its just a damn goodwrench crate motor, and I've seen 8-10 threads with people being able to at least idle/drive/log this exact setup (HEI, Goodwrench 350, base tune with only the quick start settings done).
TL;DR Don't agree to fix undocumented half-built projects, unless the customer is willing to let you start ALL the way over. Otherwise you'll chase your tail like I have for the last few days.