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).
1958-1964 Chevy Impala Bel Air Biscayne 7" Dual Chrome Power Brake Booster Kit
60 61 62 63 64 CHEVY WHEEL CYLINDERS FRONT + REAR SET BELAIR IMPALA BISCAYNE
Brake Line Kit Front Disc Conversion Kit 1958-64 Impala Biscayne Bel Air OE 5pc
1961 62 63 1964 Chevy car Impala Biscayne Fuel Gas Sender Sending 3/8" Chevrolet
Front Rear Air Ride Suspension Brackets & Bags For Chevy Impala Biscayne 1965-70
8" ZINC BRAKE BOOSTER MASTER CYLINDER VALVE & FIREWALL BRACKET IMPALA BISCAYNE