These CHEVROLET Bowtie valve covers are made of heavy-gauge steel 20% thicker than typical aftermarket valve covers greatly reducing the likelihood of leakage around the valve cover flange area caused by fasteners being over-torqued. All valve covers bear the powerful Bowtie and CHEVROLET Emblems. Stamped valve covers are offered in either tall or production height (short). Oil restricting baffles are offered in many valve covers for those who wish to maintain the PCV hookup. All valve covers are sold in pairs equipped with air breather and PCV grommets unless specified otherwise. Technical Note: Production height valve covers and valve covers with baffles will not clear most stud girdle applications. Chevy big-block or B/B refers to 1965-1996 engines.