340/mag360 exhaust manifolds

Ok, thanks Treblig, I should have clarified what I meant, so the manifold I have that works is part # 2843953 and it is a dead center dump with a 1 3/4" inside diameter date code stamped 1969, the truck manifold I have looks exactly like picture #3 you posted part# 4041466 and has the same dead center dump as yours with a 1 7/8" inside diameter, the manifold I would need looks exactly like the manifold you have pictured in the top left corner sitting on some plywood that you posted 12/30/14 just above, the reason I need this is because it is very thin at each end, if you compare the two you have you will see what I mean, in my application the cab of the truck sits very far forward on the frame so the rear of the manifold is inside the stock firewall causing clearance issues, ( I may be able to use headers to solve this but still would have to locate the right ones), also, again because of this being a truck and street rod application I HAVE to use center dumps on BOTH sides, I guess what I was hopeing here is that the one you have pictured in the top left of the plywood picture would have a larger inside diameter, OR maybe you could tell me if I could machine the one I have?, also, fyi, I can use the 80 truck manifold on the passenger side, not as many clearance issues, and lastly the engine I am using is a 1969 318 from a Dart, thanks for your help