THIS IS THE STYLE OF SPACER THEY WERE USING ON THE NATIONWIDE / XFINITY SERIES CARS TO CUT DOWN THE HORSEPOWER INSTEAD OF A RESTRICTOR PLATE. THIS IS NOT THE STYLE WHERE THE TAPER GETS LARGER AS IT ENTERS THE INTAKE.
ALLSTRA GOVERNOR ADJUSTABLE BASE PLATE 1" THICK 4-HOLES TAPERED INSERTS ALL26060
NEW WINTERS MIDGET AXLE SPACER,31 SPLINE,1 1/4" TAPERED,BEAST,STEALTH,SPIKE,XXX
1" Thick Flat Aluminum Spacers With 1/2" Hole - 4 Pack #1141
Allstar ALL56337, One Black Steel Insert 1/4In Tapered Performance Racing Parts
Allstar ALL56336, One Insert 1/8in Tapered Steel Black Performance Racing Parts