PRW 1840000 SFI-Rated External Balance 168 Teeth Chromoly Steel Flexplate for Chevy 400/383 1970-80 Early SFI 29.1 certified 0.035 inch thicker than stock flexplates Designed and built for racing Manufactured to exceed OEM specifications Features double-welded ring gears designed to withstand the RPM and stress of engine torque related to high stall converters