I have a Y block ECG 6015D engine with one C1TE head (also has a H 33 stamp) and one head with what looks like ECRR or ECR?.
I found the C1TE head as a 61-64 292, and a ECR? as a 1956-57 on a couple of websites, but I can't find anything that shows what the D suffix on the block means.
Supposedly this originally came out of a 56 truck. Any help would be appreciated, Thanks!