So I'm getting ready to build up the 218 short block I had machined and rebuilt. I remembered about the brass nuts and washers for the manifolds but not about their proper location. Did the research on this forum and hard copies of manuals I have and have the locations sorted out. What none of this research has told me is why do these Mopar flatheads have these brass nuts and washers. Not only that but two different configurations of the nuts and washers (regular washers, "conical" washers, regular nuts, and "conical" nuts). I'm thinking something to do with thermal expansion of dissimilar metals (cast iron block and manifolds and steel bolts and studs), but just a guess on my part. Any thoughts from anyone else? Regards to all