Hi Larry,
So, a little information. At the moment, I do suspect that these exhaust pipes are from a Fw 190 A, but final confirmation is not yet possible. The Sach Nr (Item number, Part number) 9-1039.04 and .08 will confirm the true identity, but unfortunately I have not been able to find a partslist that defines this. However, the first number 9- does show that these are aircraft engine related parts. Strangely, they do not feature in the BMW engine listings that I have found. I think that these exhaust pipes will actually be Fw designed parts, because they are specific to the type of aircraft that they are fitted too and they should feature in the aircraft parts list in the section for engine fittings as 9-1039. items.
I think that the .04 and .08 parts of the Sach Nr in this case are the cylinder positions for the specific parts. The BMW 801 cylinders are numbered by looking at the engine from the rear, the number 1 cylinder is in the 1 O'clock position and the cylinders are then numbered in simple sequence clockwise. Because the BMW 801 is a two-row Radial engine and cylinder number 1 is on the front row, the front row of cylinders are odd 1,3,5,7,9,11,13 and the rear row are even 2,4,6,8,10,12 and 14. This means that your pipes .04 and .08 would be the shorter rear cylinder pipes, .04 being the lowest pipe on the RHS group of exhausts, .08 being in the bottom group of exhausts under the engine. It looks to me like pipe .04 matches the lower exhaust with a distinctive kink on this picture I found of a genuine Fw 190 engine .
So, all we need now is someone with the correct partslist to confirm the identity of those numbers.
Cheers
Eng
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Photo IPMS Stockholm on internet