manifold info

Looking for stock exhaust manifold casting numbers for a 1975 dart sport 360, what I have been able to find appears only to go up to 1974 models. Trying to find out if the manifolds that are currently on my 360 are original or have been replaced sometime in the past. Not sure the of the factory headpipe size either. I currently have 2 inch headpipes but was told that a 360 should have 2/14, so I don't know. I had the head pipes made up localy about 3 years ago and the guy that did the exhaust said the old ones that were removed were 2 inch so he just replaced with 2 inch. Any info would be helpful , thanks.