Product Summary

Universal Fit, 7 Inch Brake Booster Diameter

  • Compact design adds vacuum assist for increased brake pedal response, easily mounted under the hood or floor of most vehicles
  • NEW heavy duty steel booster measures 7" in diameter and has a zinc plated finish for corrosion resistance
  • Master cylinder has a 1" bore with 3/8"-24 IFF outlets on both sides of the M/C allowing for brake lines to be run specific for your needs
  • Mounting for the booster has 3-3/8" on center, 4 bolt pattern to simplify installation
  • Mounted overall length is 11.75"

Comes as a Kit

Key Specs

MFG. Part #91031409
BrandSpeedway Motors
Brake Booster Diameter7 Inch
Master Cylinder MaterialSteel

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Compact for installation under floor or on firewall of almost any vehicle. Booster measures only 7" in diameter. Cast iron master cylinder has a 1" bore and is suited for disc-disc or disc-drum combinations.

Master cylinder features two 3/8"-24 inverted flare ports on each side (plugs are included for ports not in use).

  • Compact design to fit into small spaces under the hood
  • Universal in design, makes for a simple install
  • Heavy-duty zinc-plated steel construction to provide years of service
  • Uses standard DOT 3 or DOT 4 brake fluids

Learn more about selecting the proper master cylinder for your vehicle by reading our tech article. Brake System Selection.


  • Pushrod-to-mounting flange is 5-1/2"
  • Four bolts on 3-3/8" centers
  • Booster is 3.75" thick
  • Master cylinder combo is 11.875" from end of the master cylinder to the firewall
  • (4) qty 3/8"-24 outlet ports (2 plugs included)
  • 8" from mount to outer edge


MFG. Part #91031409
BrandSpeedway Motors
Brake Booster Diameter7 Inch
Master Cylinder MaterialSteel
Brake Booster TypeVacuum Diaphragm Single
Outlet CountTandem/Both Sides
Outlet Fitting3/8"-24 (4)
Master Cylinder Bore Size1 Inch
Brake Booster MaterialSteel
Overall Length11.75"
Master Cylinder Port Sizes3/8"-24 IFF
Bolt Hole Pattern3.38" x 3.38"
Centerline of Holes3.38"
Reservoir IncludedYes
Sold in QuantityKit