Adjust. Rocker Arm Nuts w/12 Point Heads

One of the more aggravating things found in many high performance engines is constantly having to re-adjust rocker arms. Fact is, up until ARP introduced the patented Perma-Loc adjuster, there wasn’t a ‘poly lock’ on the market that you didn’t have to keep adjusting. There are several important reasons why ARP’s exclusive Perma-Loc rocker arm adjusters won’t loosen like others. First, the adjuster body material is premium grade 8740 chrome moly steel which has been heat treated all the way through, not just case hardened. This eliminates common thread movement. Threads are machined exactly perpendicular to the bottom of the adjuster, so it seats evenly and applies pressure on a full 360deg. circle. Lastly, the set screw is machined flush on the bottom, so it will have optimum contact on the rocker arm stud. ARP Perma Locs are easy to use. The compact 12 point head is designed to hold your wrench in position while you lock the set screw with an allen wrench. With most ‘poly-locks’ you have to invest in a special tool to do this job. 190,000psi tensile strength.


16pc pack
Thread Size Shank Size Length Application
AR300-8243 3/8-24 .550 1.200 Aluminium Rocker
AR300-8244 3/8-24 .600 1.200 Aluminium Rocker
AR300-8245 7/16-20 .550 1.200 Aluminium Rocker
AR300-8246 7/16-20 .600 1.200 Aluminium Rocker