Ok, I'm cheap! I found a guy to weld up the manifold and I've been at 25 mpg the past couple tanks. Yay! Not good enough though. According to JR my timing should be around 45 deg at 7lbs MAP but I'm right around 35 degrees. 22 degrees at 10lbs MAP.
Picked up a new knock sensor today and just installed it, I'll let you know how it goes
Edit: No effect on timing, exactly the same
