The booster mounts with a 4-bolt pattern. The 4 bolts are in a perfect square and are 3 3/8" apart (center to center).
Chrome 7" Dual Power Booster + Milled Master Cylinder & Bracket A-Body Disc Disc
Leed Brakes 2L6B4 7" Dual Power Booster 1-1/8" Bore Master Disc/Disc Chrome
Leed Brakes 761A3 7" Dual Power Booster 1-1/8" Bore Master Disc/Disc Zinc
CHROME 7" Dual Power Booster Milled Master Cylinder & Bracket A Body Disc Disc
7" Dual Power Booster 1-1/8" Smooth Top Master Cylinder 4 Wheel Disc CNCB70008
Leed Brakes E61A3 7" Dual Power Booster 1-1/8" Bore Master Disc/Disc Zinc