My dad has a 383 in his road runner with a 76 400 intake and carb. Do these have an EGR valve in them? and can you plug them or is it better to use different intake. He has an older intake for a square bore carb, but is using this on for now. Thanks.

Last time I carried around an iron 400 intake with a thermoquad on it, I thought an aluminum intake would be a nice step up.

Yes the 74 and later manifolds have EGR Valves.
Yes you can plug them by bolting a flat plate wit gasket in place of the EGR valve.

If you just need a manifold it is fine but like he said an aluminum one is nice.

Trying to talk him into new intake and carb, he said it is just for cruising,until I blew the doors off of it with my dart. That was fun! I told him to let me have it for a day with a new carb, intake and electronic ignition. He has the ignition in his 68 newport convert. I think I convinced him to try it in his Road Runner after yesterday!