These Pro series connecting rob bolts from ARP are cold-forged to ensure molecular integrity. They are heat-treated prior to thread rolling and machining and are rated at 190,000 psi. The Pro series kit has 12-point nuts, and comes complete with hardened parallel washers for an even load distribution and accurate torque readings. Bar none these are the best rod bolts you can buy for your Triumph TR250, TR6 and GT6. Cross Ref.# 322-828