Ellis made 2 and 3 carb manifolds for almost every inline 6cylinder that was made in the 50's. It could fit your Chev or it could be something that the previous owner bought thinking it was a Chev. I have one that fits a GMC and it is marked GMC. Usually they have something stamped on the middle runner. Most single barrel carbs will work but its a lot better if they are matched. I have a pair of Zenith 28's that I think were original to some military vehicle, but they are the same Part NO. If you can get a good measurement of the distance between the two outer runners on your Chev, you can tell if it will fit the Chev or not. If it doesn't fit and its not marked, it could be anything. Fenton headers can still be bought to fit your chev. If you can figure out what it fits and it doesn't fit in your plans, it will probably fetch $200 or so on eBay.