1" thick adapter plates allow for a clean and easy install of any Snow Performance nozzles on carbureted applications using a Holley, Edlebrock, or Carter 4500 Carburetor. Comes with necessary gaskets/studs needed for install. (Machined with (2) 1/8" NPT ports) Warning! When using a injection plate a solenoid upgrade part# 40060 must be used to prevent vacuum siphoning.