Hi guys, hope this isn't an obvious answer question. My 351M has an EGR valve that is plate mounted sitting under the carb and above the intake manifold. It has a vacuum line coming in from the side which is routed to a PVS switch and a second line that is going back to the carb. If this unit is supposed to recirculate exhaust emmisions ... where do they come from? Is there a mystery port in the intake manifold that I don't know about?

 

You guessed right. There's an exhaust crossover cast in the intake. The inside of the EGR spacer plate has a cavity to collect exhaust routed through the intake.

 

fmc 400
Thank you. I thought it might be that simple but it's easier to ask than it is to disassemble.

 

fmc400 is correct, there is a passage under the intake manifold, the exhaust cross over passage, that the EGR valve pulls its exhaust charge.
The actual purpose of the cross over is to route hot exhuast gas under the carb when the engine is cold to aid warm up and cold weather driveability.
Ford also used this passage to draw exhaust gas up to the EGR valve.
The EGR doesn't really recirculate exhaust emissions. What it does do is meter exhaust gas into the intake charge to dilute it. This reduces peak combustion temperatures and helps reduce nitrous oxides emissions.
Here's a 400 intake. The EGR passage is in the red square.