This is a great upgrade from a single diaphragm booster.
For Chevy GM Universal 8" Dual Diaphragm Silver Power Brake Booster Street Rod
Chrome Chevy 8" Dual Disc Disc Power Booster + Milled Master Cylinder & Brackets
Chrome Chevy 8" Dual Disc Drum Power Booster + Milled Master Cylinder & Brackets
GM 8" Dual BLACK Power Brake Booster 1 1/8" Bore Wilwood Master Cylinder + Valve
GM Full Size Car 8" Dual Zinc Brake Booster Master Drum Drum Kit 1-1/8" Bore
1967-72 Chevy Truck 8" Dual Brake Booster 1 1/8" Wilwood Master Cylinder + valve