I recently picked up a pair of 57 exhaust manifolds for our 56 Ranch Wagon project off the local Facebook Marketplace and have a few questions; The left side manifold appears to be the high flow EDB-9431 casting, but the right side, even though it looks like the square top high flow has the casting # B9AE. Is this a replacement for the EDB-9430 and will it flow the same as the left side?

Second question has to do with the drilled little plug between the center ports. I assume this is to add heat to the choke tube, but it's not on my 56 manifolds. I'll be using a modified "B" intake manifold without the choke tube so do I need to do anything to this plug or just leave it?

Last question; Looks like there was a casting flaw in the way of a "V" on the #4 exhaust flange. Can I leave it alone and hope the gasket will seal it off or does it need to be filled? If it needs to be filled is there a high heat epoxy I can use or does it have to be welded and ground? Here are some pictures;

  Ron Lane,  Meridian, ID