Engine Kits

ARP Adjustable 3/8-24 Rocker Arm Nuts .550 Outside Diameter
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ARP Bolts

ARP Adjustable 3/8-24 Rocker Arm Nuts .550 Outside Diameter

Part #: 300-8243
List Price: $104.56
Our Price: $69.69
You Save: $34.87

Adjustable 3/8-24 Rocker Arm Nuts, For Aluminum Rockers, .550 Outside Diameter, 1.200 length, Set of 16, ARP 300-8243 Rocker Arm Adjusters.

ARP Perma-LOC or Poly-LOC



• Exclusive 12-point head
• Patented design
• Heat-treated premium grade A 8740 chrome
moly steel
• 190,000 psi tensile strength
• Precision machined threads
• Locking set screw ground flush with rocker arm stud
• Doesn’t require special tools

One of the more aggravating things found in many high performance engines is constantly having to re-adjust rocker arms.

Until ARP introduced the patented Perma-Loc adjuster, there wasn’t a “poly lock” on the market that you didn’t have to continually tighten. There are several important reasons why ARP’s exclusive Perma-Loc rocker arm adjusters won’t loosen like others.

First, the adjuster body is heat-treated all the way through (not just case hardened). This eliminates the thread “movement” common to others. Secondly, the threads are machined exactly perpendicular to the bottom of the adjuster, so it seats evenly and applies pressure on a full 360° circle. Lastly, the set screw is machined flush on the bottom (not pointed) so it will have optimum contact on the rocker arm stud.

You’ll find ARP Perma-Loc’s easy to use, too. The compact 12-point head is designed to hold your wrench in position while you lock the set screw with an Allen wrench.

All in all, they’re the best you can buy!

Brand ARP
For Use with Stud Girdle No
Minimum Rocker Slot Width (in) 0.550 in.
Outside Diameter (in) 0.550 in.
Overall Height (in) 1.200 in.
Part Type Rocker Arm Nuts
Product Line ARP Perma-Loc Rocker Arm Adjusters
Quantity Sold as a set of 16.
Rocker Arm Nut Style Polylock
Rocker Arm Style Full roller
Rocker Stud Thread Diameter 3/8-24 in.

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