MR. Gasket Headlock LockingHeader Bolts - 3/8-16 X 3/4 Inch - Set Of 12

Headlock� Bolts eliminate the need for lock washers, Period. That's because each Headlock� Bolt features 24 equally-spaced, stainless steel teeth serrations that bite into and hold onto the attaching surface-eliminating the need for lock-washers.
Fits: AMC 290-401. Chevrolet Small Block 262-400, Chrysler Big Block 383-440 Wedge Engines, Pontiac 326-455, and Oldsmobile 330-455
Features:
12 per Package
Includes a ball-head/hex-key socket-installation tool that makes it easy to get them started
410 stainless steel
Minimum 180,000 PSI tensile strength
24 equally spaced clockwise teeth