These were for sale as Avro Anson
I knew they were not Anson so I acquired them and have been investigating.
The larger aluminium one is easier to identify by the assistance of a Douglas stamp.
It appears to be the exhaust outlet from the engine.
The brown on green primer paint remains suggest that this is most likely from a faded Olive Drab C-47.
The three part stainless steel item has no part numbers - a small plate with 001 G and another with 7-4 and no other identification.
A longer search of hot end exits from radial engined American aircraft and I find that it is a match for a DC-4/C-54 exhaust outlet.
Can anyone confirm the identities?