Holley 4BBL Vacuum Secondary 600CFM Stage 1 – 1850S1




  • Strip to bare metal, inspect for defects, then apply dichromate coating for brilliant gold finish.
  • All body surfaces machined for maximum gasket sealing, ensuring consistency and reliability
  • Assembled with reusable gaskets for ease in tuning and service
  • Machine body surfaces for maximum gasket seal
  • Metering blocks are hand selected and all circuits and passages are checked for casting flaws and obstructions, as well as proper sizing
  • Nitrophyl solid composite float that can’t crack or sink.
  • Position boosters precisely in center of venturi for best flow and equal signal
  • Select only the highest flowing castings
  • 1 YR warranty all parts and labor
  • Vacuum Secondary operation modified to provide more response to secondary spring changes.

Additional information

Weight 15 lbs
Dimensions 15 × 15 × 15 in


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