I do not have a vented cap (as far as i know). I T-d the line in and ran the lines to an LT1 PS res I had laying around. No issues with mine.
Can see it in the lower section of this pic next to windshield washer fluid
BUT, even with no issues, I want to clean up that area so when I do a cam swap I will go to a regular pump with attached reseviour, that will remove some hoses and possibliyt of leaks.