try this link

https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=845727

If you are looking for a new you can find one at obschevy.com. there maybe other companies that sells them. Obsolete chevy parts Co. has them listed as p/n 3836566 for 1954-58, p/n 3835528 for a 1940-53, p/n 838217 for a 1937-39, and p/n 836867 for a 1933-36.

http://i1291.photobucket.com/albums/b554/stovebolt56/rockershaftoil_zps8d58efdf.jpg

I took my 55 head and used it for parts on my 56 head. My 56 and my 1958 -62 tube was cut and crimped towards the top (looked like a "L" shaped. My 55 was not and the tube went around the rocker arm rod back down towards the bottom of the head. The guy at the machine shop told me they crimped them to force more oil to the rocker arms.

Here is a pic off my 3836848 head in my 1958-62 "235" block. http://i1291.photobucket.com/albums...e/2013-01-20_08-31-09_48_zpsaaa73812.jpg and http://i1291.photobucket.com/albums.../2013-01-20_08-31-48_263_zps3bd66482.jpg

Here is some pics off of my 1955 block with the 3701887 head http://i1291.photobucket.com/albums.../2012-12-11_09-00-01_877_zps92ecdb86.jpg and http://i1291.photobucket.com/albums.../2012-12-11_09-00-38_933_zps646d4462.jpg

Here is some pics off my 1956 block with the 3836848 head. http://i1291.photobucket.com/albums/b554/stovebolt56/2012-12-11_09-03-39_835_zps0a488e07.jpg


Some one else can chime in and give thier knowledge but I can only tell you what I have.

"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my sweet ride." -Amen

56 Chevy 3100