F55P
1955-1st series big truck standard engine = 235 (6000 series), Flint, MI assembly plant
http://www.1954advance-design.com/chev-specs/1955-1st-Chevrolet-t-ser.pdf

54/55 235 head
3835913
http://www.1954advance-design.com/Stovebolt-engine/casting-numbers.html