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Part number: 300-8249
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Product Details
ARP 300-8249 Rocker Arm Nuts
Products specifications
Body 1.200/1.485
Diamater .750
For Use with Stud Girdle Yes
Length 2.050/2.615
Notes Contains both 2.050 in. and 2.615 in. length rocker arm adjusting nuts.
Outside Diameter (in) 0.750 in.
Overall Height (in) 2.050 in.
Quantity Sold as a set of 16.
Rocker Arm Nut Style Polylock
Rocker Arm Style Full roller
Rocker Stud Thread Diameter 7/16-20 in.
Shank .600
Thread 7/16-20
Stud Girdle

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 wasnt a poly lock on the market that you didnt have to continually tighten.

There are several important reasons why ARPs exclusive Perma-Loc rocker arm adjusters wont 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.

Youll find ARP Perma-Locs 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.


  • 12-point head with special shouldered stop to hold wrench. Eliminates need for special adjusting tools.
  • Forged in-house from 8740 alloy chrome moly steel and heat- treated throughout (not simply case hardened, as others are).
  • Bottom flush-ground perpendicular to threads.
  • Threads are precision CNC-machined exactly perpendicular to the bottom of adjuster to ensure an optimum seat and even pressure.
  • Set screw has flush-machined tip for optimum contact and seating on stud.
  • Threads machined for maximum engagement.
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Great customer service and product pricing! Received tracking number very quickly and will recommend to anyone!!!!

For the over-the-winter garage storage of my 911, the Rail Ramps Flatstopper product has eliminated the need to move the car over the winter in order to avoid the tires developing flat spots.
Cheapest price online.  Great products.. really fast shipping.. no hassle
These guys had great pricing and got my order to me very quickly.  I would do business with them again for sure!
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