64-72 Chevelle Wilwood Chrome/Polished Master Cylinder and 8" Dual Diaphragm Brake Booster with Brackets. This master cylinder features chrome/polished finish with chrome anodized machined aluminum top. Master cylinder outlets are 1/2-20 UNF and come with adapter fitting for 3/8-24 and 9/16-20. Master cylinder works with both disk/drum or disk/disk applications. Booster is a 8" dual diaphragm and is a great upgrade from a single diaphragm booster. Dual diaphragm boosters offer 19% better stopping over single. Kit also includes Wilwood adjustable proportioning valve with mounting bracket and stainless brake lines.