Ive got one of the early 261's, '54 & 55 1ST with the short high mount pump. You can also install a 55 2nd - 62 with an adapter plate to install the original water pump.
Later engines have full - flow oil filters but older blocks can be converted to full flow filration easy enough when torn down.


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