I am currently doing an overhaul on a 76 fe 390. Its time to clean up and install the intake manifold. It s extremely dirty and has tons of buildup. There is some kind of a cover on the bottom made of sheet metal. Its kind of loose and there is a ton of build up under it. I don't know exactly what its purpose is. What I'm asking is should I take it off and clean under it and is it possible to reattach, it appears to have one rivet holding it in. Can I do away with it? Its kind of loose. Any input would be appreciated. I am new to fe motors and need to finish this thing as I need the truck.

 

You should keep the piece of sheetmetal.
It's a heat shield, it's function is to keep the oil that's splashing around in the valley from coming in contact with the hot exhaust crossover passage that's under the manifold. If oil comes in contact with the passage it can "coke up" that is turn to a grainy, gritty carbon, not good for the oil.
These are held to the bottom of the manifold with a couple of drive rivets. These can be drilled out and new ones driven in with a hammer. My local hardware store has them in stock.

 

Thanks Mike. I went out there and messed with it some. I think that's what happened. One of the rivets is missing and there was a bunch of hard crusty material under it . I will clean it and replace it. I was just afraid to mess with it before I knew. Wasn't sure how big a task to reattach it was. I'm ready to reinstall the engine and out in the country by myself with no easy ride to town. I was able to get the rivets out and may just tap the holes and lock tight or jb weld some bolts in them.

 

In case anyone else reads this thread or has the same problem here is from free advice. After finding mine hanging down with a rivet completely missing, I cut the other one off and cleaned out from under it. Turns out unless your lucky enough to live around a supplier the drive in screw type rivets can be hard to locate. Secondly after speaking with a machine shop he said this was a common problem and he often finds them laying on top of the lifter tray. So rather than take a chance on that ,I decided to have mine welded on. Didn't cost but ten bucks and it eliminates the chance of the rivets getting loose in your engine or the heat shield bouncing around your pushrods. If you need to clean out from under it just use a propane torch, heat it up and it will burn of any coke built up underneath then just blow it out with compressed air. I looked all over my two horse town and couldn't find those rivets, plus the idea of it happening again after dumping 500$ bucks into was just unacceptable. Hope you this helps.