The port(s) in the head aren't related to the EGR system, they're for air injection
. If you won't be using air injection at the cylinder head (even if you will be injecting air at the catalytic converter, if any), you can block off the system with the factory blockoff plate, part number 3751 249 with gasket 4275 834.
The EGR passages are in the intake manifold â€”Â that's where the EGR valve is bolted on. If you won't be running EGR, you can simply leave the valve in place but disconnected, or you can install the blockoff plate 3671 447 with an ordinary EGR valve gasket.
The decision of whether to run or omit EGR depends on what kind of carburetion and ignition setup you'll be running and what kind of emission tests you have to pass with the truck.
Too many people who were born on third base actually believe they've hit a triple.