Need your opinons!

[BMSJaX]

Alright I have an odd 'problem' with my 350 and I think I know what it is but I'd like to know your opinions without tellin you my thoughts to see if we think alike before I go through the effort of fixin it to find out I was wrong.

Symptoms:
1. Poor fuel economy- 10 MPG or less when I should be gettin 12 to 15 (Q-jet 750cfm)
2. Badly fouled spark plugs(Only 2 months old and are BLACK)
3. Slightly low vacuum(fluctuates between 12-15 at idle)
4. Poor low-end power with great top-end power
5. Cannot run with proper timing settings(6-12 adv base and it dies on take-off in first of if you hit the throttle harder than feathering it)
6. Timing by 'feel' and it runs great but the mark is way off the scale(20-30 adv range base)

Alright tell me what you think!