3701887 is a 1953 235 cylinder head

The 1223 is probably a date casting code that might be I223, which would decode to:

I = September
22 - 22nd
3 = 1953

Wait for Tom to confirm or correct.

What is the block casting code and the block date casting code?
http://1954advance-design.com/Web%20images/casting-code-photos/low-press-codes-ser-nums.html

So, it looks like you have a 1953 235 head that works with a later high-pressure block. The 1953 was a transition year for the 235 heads and blocks.

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.