Re: 1967 California Emissions ?
What's the part number and date code on the carb? The L30 327 had the 4 barrel. A picture of the trim tag may also help.
SBC valve covers were the same in 67, whether emissions or not (no vent or fill holes). The venting was through the vent tube at the top rear of the engine. You want to look at UPCs K19 and K24 in the AIM for specific detail.
CRG site info:
CRG Research Report - 1967-1969 Camaro Carburetors
CRG Research Report - 1967-69 Emission Systems