Manley Turbo Tuff I Beam Rods are made using forged 4340 aircraft quality vacuum degassed material, made for the EJ205 EJ257. Manley Turbo Tuff rods are machined in house, in the USA, to ensure the highest quality product. Each rod is shot-peened after machining and magnafluxed. The bores are round with no taper and these rods use APR 2000 cap screws for ultimate strength.