eBay 133942145662 serial 376487 is out of a 1926 M Star.
Interesting to note even back then it doesn't give a casting date just 9 D O meaning ? Sept Day ? Year ?
Aren't all the exhausts 4 or 6 cyl pre 1930 with the castellated nut screwed into the opening. Pic's of 6's show the castellated nuts 14L, 15L. Leaside aftermarkets only say Exhaust Manifold to Exhaust pipe packing nut 65 cents, US aftermarkets say nothing.
Where Are You From? Ottawa Ontario Canada
Do You own a car built by Durant? 1932 614 sedan made by Dominion Motors
I have about 30 four cylinder engines and it is my observation that 1922-24 Stars used the W4 with round plugs in the water jacket and a slip fit, rear dump manifold. The 25-early 27 used the W5 with bolted plates on the water jacket and a rear dump manifold with threaded jam nut. Later 27 Stars went to rubber engine mounts, side mount steering box, and a front dump manifold with threaded jam nut. About when Durant started production again they used the W5 and reverted back to round water jacket plugs, and front dump manifold with threaded jam nut.