Need TBI troubleshooting help

[Rust Buster]

Hi guys,
First a little background on the truck
1988 V30 (1 Ton 4x4 Dump Truck, manual tranny, TBI 350)
This is the mountain neighborhood plow truck and never goes off our private roads. I did a complete rebuild of this truck this fall, all major systems and sensors are new, to include:

Rebuilt stock TBI
Long tube headers with heated O2 sensor
Coolant temp sensor
IAC
Oil pressure sensor
MAP
TPS
EGR Valve
EGR Solenoid
Speedway Motors TBI wiring harness
Distributor (stock replacement)
Ignition Coil
Plugs/wires
Fuel pump

Here's the problem. Truck starts and runs/idles pretty well. It does have a delay/say when you open the throttle. I have all the vacuum lines capped at the TBI except for the PCV port and MAP port. The only sensor I have not changed is the ESC module, but one is on the way.

When I check the timing (using the correct method by unplugging the timing wire), it runs very very rough and will cut out at 0 degrees. It only idles smooth at a ridiculous amount of advance, that is off the indicator plate. It will run decent at about 8 degrees advanced, but anything close to 0 gets a rough idle.

If I unplug the ESC module, there is no noticeable difference in anything. Is that normal? Also, the EGR valve doesn't seem to be doing anything. Normal? When I run a scan, I get about 6 codes, relating to EST, Coolant temp sensor, inlet air temp, etc...but I'm not sure how accurate this is. There is a TON of vacuum at idle on the PCV port.

It runs pretty good at that advanced timing, but with all the codes and the sag/hesitation when you open throttle, I am assuming there is an issue and better performance to be had.
Any ideas?
Thanks in advance!