Product Summary

Universal Fit, Steel, Zinc Plated

  • Used in rear of Ford cylinder heads to plug Thermactor upstream air ports
  • Threaded insert provides correct thread size to mount engine accessories when installed in front of head
  • Zinc plated steel for corrosion protection
  • Easily threads into cylinder head with large flat-blade screwdriver
  • Set of four will do one pair of cylinder heads front and rear

Key Specs

MFG. Part #5775804
BrandSpeedway Motors

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Set of great EGR steel plugs. These plugs are constructed from solid steel and feature a nice zinc finish. Use to plug emissions passage on rear of Ford cylinder heads and to reduce thread size on front of the cylinder head to allow accessory bracket installation. Sold as a set of 4.

  • Steel construction
  • Zinc finish
  • Set of 4
  • 5/8"-11 External (male) threads
  • 7/16"-14 Internal (female) threads


Small block Ford factory and aftermarket cylinder heads

CARB Warning

For race/ off road use or for use on pre-1966 vehicles.

Emissions warning: this part only legal for sale or use in California for racing (competition) vehicles which may never be used, registered, or licensed for use upon a public highway, or if installed in vehicles model-year 1965 or older; motorcycles model-year 1977 or older; or off-highway recreational vehicles (such as off-road motorcycles and all-terrain vehicles) model-year 1996 and older. Any other use renders the vehicle tampered and not legal for use on California public highways (any public street or roadway, public dirt road, public park, or publicly maintained right of way open to the use of the public for vehicular travel). Violations subject to $37,500 penalty per violation per vehicle, revocation of registration, loss of use on California public right of ways, and proof of correction for tampering. There are similar restrictions and penalties under federal law and the laws of all other states with penalties under federal law of up to approximately $45,268 per tampered vehicle and/or engine.


MFG. Part #5775804
BrandSpeedway Motors
Sold in QuantitySet
NotesThermactor Air Insert Plug
Material TypeSteel
FinishZinc Plated