Hard to tell by the pic.
These cars had a lot of vacuum controls.
Could be EGR, purge, air injection, or.
Some of these cars had anti diesel, & vacuum idle speed.
1st I would look at the underhood vacuum sticker to see what your choices are.
Thru a process of elemination you may get it that way.
In the diagram they draw it in relation to where the relitive location of the part is.
If any hoses are still connected, trace it back & compare to vacuum diagram.
Look for any port markings like "can", "carb", "1 & 2" etc.
Look for a part number.
Last case if you had a computer engine wiering diagram you could figure it by the wires.
Hard part about matching it up is designes may have changed, so replacement part pics don't look the same.
Looks like it's melted a bit along with the wire.
Depending on the factory these 307's had a different vacuum systems.
