ASTM A234 Material: Equivalents, Grades, Specification MWalloys Wilwood 261 16797 BK Wilwood Mopar Compact Tandem Master Cylinder Kit w Combination Valve 1in Bore Black. Wilwood 261 16797 BK Wilwood Mopar Compact Tandem Master Cylinder Kit w Combination Valve 1in Bore Black Wilwood now makes a performance master cylinder with a flange specifically for Mopar's unique four bolt pattern. The rectangular mounting flange of our Mopar Compact Tandem master cylinder matches the A body, B body and the E body firewall mounts in the 1960's and 70's. Available in 15 16", 1. 00" and 1 1 8" bore sizes without pushrod, 15 16"" and 1. 00 with pushrod and Mopar style eyelet. Available in either a chrome powder coat finish or a glossy black E coat to complement any engine bay. These kits are available that include a combination valve with a hydraulic brake light switch, adjustable proportioning valve, bracket, and plumbing.