Ok so here's my deal. I have looked everywhere for a vacuum diagram for my vehicle and can't seem to even get close. Can you help me find a good vacuum diagram???

My specs follow:

1977
Ford (of course)
F250 Hiboy
Non emission
1406 Edlebrock ie. 600 cfm automatic choke
400ci 6.6L eng
C4 Manual transmission
4x4
8 Lug axles
Power steering
A/C (not installed currently)
Power Breaks
NON EMISSION (did i mention that?)
Two tone paint, black and white
Red interior
AM/FM CD stereo
5th wheel package incomplete for now
Grant wood steering wheel
32in tires

anything else?

oh I have one other thing,

Positive cable from battery runs to starter sol then to a blue finned cube thing next to solenoid. that box has three cables not labeled and one of those three is not attached to anything.

any ideas?

 

I recommend searching this forum (in the toolbar above) for posts by mil1lion or something like with keywords. He is the fountain of overflowing information.

I've seen posts in here with vacuum line routing but didn't track or copy 'em cuz my rig has minimal hoses (THANK GOODNESS).

 

Power brakes, along with the automatic transmission modulator valve both run to manifold vacuum. You should have a vacuum tree on your manifold for this.

The heater controls are sourced by a vacuum check valve. One side of the check valve is sourced by manifold vacuum. The heater control vacuum line as well as a vacuum reservoir connect to the other side of the valve.

The vacuum advance on the distributor typically goes to ported vacuum, which is the higher of the two small 3/16" vacuum ports on the front of an Edelbrock. If you have an EGR valve, it too is sourced by ported vacuum, through a ported vacuum switch. There were many varieties of these systems used throughout the model years, but what I've just listed is the simplest.

Any vacuum port which is unused must be plugged.

Can you post a picture? That almost sounds like the voltage regulator with some modified wiring.

 

Could it be a dual battery isolator?

 

Battery isolator was my first guess.