Anytime a set of rod bolts is changed, the safest way to do it is to have the rods reconditioned at the same time to be sure the big end stays round, and the correct size. I ran the rod room for a big machine shop in Nashville for a few years, and that's what we reccomended every time we sold a set of ARP bolts.
The AERA connecting rod manual I have specifies 35-45 ft/lb. torque on all 250 connecting rods. (Yes, that is 48 N/M) If you swap for ARP bolts, remember the torque value changes. Follow the package directions, and I believe the stronger-alloy bolt needs 50 ft/lbs., not 45, and a special lubricant they provide in the package along with the new bolts. The "headless" bolt actually has a flat spot built into the top of the bolt that catches a corresponding flat area on the rod to keep the bolt from turning while it's being tightened. Always torque an ARP bolt at least twice after installing it. Drive the bolt into the rod body, lube the threads, torque them up, then loosen and retorque at least once to be sure the right amount of stretch is on the bolt. On the really hot race engines, we use a special micrometer and measure bolt stretch, not torque, to determine when the bolt is tightened properly.
Jerry
