As performance levels increase, an O.E. style flexplate just won't cut it and a stronger option is a necessity to prevent transmission and/or converter failure. B&M has you covered with our high performance flexplate designed for 1955-1985 400ci small block Chevy V8 engines (externally balanced) with two piece rear main seal. Features include high tensile strength steel construction to resist elongation and cracking, dual bolt pattern 10.75 or 11.5 in. converter mounting locations, 168 tooth ring gear with double-sided welds for added strength and comes with SFI 29.1 safety certification insuring the ultimate in safety and performance. The assembly is then Zinc plated and treated with a Chromate Conversion Coating for added corrosion resistance and durability. B&M SFI approved flexplates are ideal for extreme duty race applications as well as street cars, tow vehicles or other vehicles needing the added protection and toughness that B&M has been delivering since 1953. Compatible with Powerglide, TH350, TH400 and TH700R4 automatic transmissions.