Looks like a crankcase breather cap to me, going to l flow way more than a pcv valve. Yes you do need a breather cap of some kind.


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