【Fitment】Compatible with 4 barrel carbs with a square bore base: Fits for Holley 4150/4160, Fits for Barry Grant, Fits for Carter Fits for E-delbrock, Fits for Small/Big Block Chevy, Fits for F-ord, Fits for C-hrysler M-opar engines. 【Excellent Quality】Phenolic material is a type of plastic resin which has excellent insulating properties,Made of phenolic resin and engineered to reduce heat transfer from the intake manifold to the carburetor that provides a denser air/fuel mixutre for increased power and efficiency. 【Open Design Spacers】The open design spacers increase plenum volume for improved high rpm power, while 4-hole designs increase mixture velocity for improved low-speed and mid-range torque. 【Package includes】Package Includes mounting hardware and gaskets. 【Aftermarket Service】YUCHENSHLP brand is a professional auto parts seller,backed by team of engineers and quality control experts in the United States. If you have any questions, please feel free to let us help you solve them. Thanks!