Product details:

Thickness, Black, 2.030 in. Throttle Bores, 4-barrel Dominator Carb Mounting, Each - Quick Fuel phenolic carburetor spacers are specifically designed for race applications only. They're manufactured from phenolic material, a type of advanced plastic resin that offers excellent insulating properties, so it can keep the fuel in 4-barrel (4150/4160 Series) carburetors cooler for more power. They're offered in open or 4-hole versions, in different thicknesses. The tapered 4-hole spacers have specially contoured holes to increase air velocity under the carb. These carburetor spacers are not designed for street use.