Hey jasrking, I the pics in your original post I noticed the valve cover has the hole for the fresh air inlet used with PCV system. I' ve only seen that on 261.
You might check the block cast number, capt. bars etc .

Last edited by Phak1; 10/20/2025 12:35 PM. Reason: Typo
BC
1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc
1949 GMC 250 project in waiting
1960 C60 pasture art
Retired GM dealer tech. 1980 - 2022