16 Marvin McAfee of MCE Engines is a big advocate of carburetor spacers because they improve torque. He stresses the different thicknesses and their effect on torque. You will have to try a number of thicknesses if you're fine-tuning power. However, this one is the most common—about one inch—from Edelbrock. It's the same thickness as a stock 289/302/351 spacer.