On both my 48 Plymouth and my 29 "A" I used a Walker. In both cases the fit was perfect as original. On my 51 I am running a Walker that is perfect for my application, SBC with auto and air.
I pulled the listing below out of the PDF file from Walker's catalog.


Chevrolet BOTTOM OUTLET RIGHT
Cobra Standard Series
Year Model Part Number Top Inlet Bottom Outlet See Notice Max-Air# Cooling Comp.#
1932 C-512-1 Left Right NDN RS WS-50 CCI-1750
1933 Master C-510-1 Left Right NDN WS-50 CCI-1750
1934 Standard Z-508-1 Left Right NDN ZZ WS-50 CCI-1750
1934 Standard Z-508-1 Left Right NDN ZZ WS-50 CCI-1750
1934 Master C-509-1 Left Right NDN WS-50 CCI-1750
1935 Standard Z-508-1 Left Right NDN ZZ WS-50 CCI-1750
1935 Master/Early C-509-1 Left Right NDN WS-50 CCI-1750
1935 Master/Late C-505-1 Left Right NDN WS-50 CCI-1750
1936 Master C-505-1 Left Right WS-50 CCI-1750
1937 All C-501-1 Left Right WS-50 CCI-1750
1938 All C-502-1 Left Right WS-50 CCI-1750
1939 All C-503-1 Left Right WS-50 CCI-1750
1940 All C-504-1 Left Right WS-50 CCI-1750
1941 All C-504-1 Left Right WS-50 CCI-1750
1946 All C-513-1 Center Right WS-70 CCI-1770
1947 All C-513-1 Center Right WS-70 CCI-1770
1948 All C-513-1 Center Right WS-70 CCI-1770
1949 All C-535-1 Center Right CCI-1740
1950 All C-535-1 Center Right CCI-1740
1951 All C-535-1 Center Right CCI-1740
1952 All C-535-1 Center Right CCI-1740
1953 All C-535-1 Center Right CCI-1740
1954 All C-535-1 Center Right CCI-1740
1955-57 V-8 C-567-1 Center Right V-8 CCI-1740
1955-57 S-6 C-567-1 Center Right S-6 CCI-1740
Notice: V-8 V8 Mounting brackets.
S-6 6 Clylinder mounting brackets.
NDN No dummy neck.
zz Only available in Z-line series.
Order

~Jim