Our next step up from the 400SS features Carbon/Kevlar reinforced bands, high capacity 34 element sprag race and semi-automatic valve body, which allows you to select gears manually, or leave it in drive for full automatic shifting. This trans features a 6 clutch direct clutch pack with semi metallic frictions and a billet steel forward clutch hub to improve the horsepower rating to 725HP. This trans includes our 400HS high stall converter with up to 2500 stall, and additional converter choices are optional up to 4000 stall if needed. This trans is great choice for the 572 Crate engines as well as any high output Big block.