Edelbrock Fuel Injection Manifold for Mustang 5.0 - Question

[Dr G]

Hello - I just bought an Edelbrock fuel injection manifold for the 302 based 347 in my 56 F100. Currently the engine has an Edelbrock Air Gap manifold with a Holly 4150.



The new manifod has some features that I do not currently have. And I am trying to figure out what they are for so I can assess how to deal with them.



Regarding the large hole in the backside of the manifold. It leads into the lifter valley. What is this for? Exhaust gas recirculation? I assume I can just block this off.

Then there is this circtuitous passage leading from the throttle body area to the cylinder head shown in these two photos (entrance and exit):





I am not even sure that the heads on my engine have anything for this passage to lead into. I was planning to also block this off.

It would be good to know what these features are intended for, so that I can be confident in ignoring them. If anyone can lend assistance it would be most appreciated.

Gustave