- Joined
- Apr 13, 2009
- Messages
- 12,731
- Reaction score
- 3,781
- Points
- 113
- Location
- Calgary, Canada
- Vehicle Year
- '91, '80, '06
- Make / Model
- Ford, GMC,Dodge
- Engine Size
- 4.0,4.0,5.7
- Transmission
- Manual
- 2WD / 4WD
- 4WD
I've always assumed that, in general, below the throttle plate is manifold vacuum, and above is ported vacuum. So look at the centerline of the throttle plate and go from there.