SpeedFactory 4140 Head Stud Kit for B/H Series Engines

SpeedFactory Racing 4140 Head Studs - Honda/Acura B Series VTEC & K Series Engines

If you're running boost or building a high horsepower B series VTEC or K series engine, you need head studs instead of factory head bolts. The SpeedFactory 4140 head stud kit is built to handle forced induction applications up to 800+ horsepower. These studs have a 210,000 psi tensile rating, oversized forged nuts and washers for better load distribution, and a dog point design that seats the stud in the block for consistent torquing. They're a direct drop-in replacement for your factory head bolts, so you don't have to modify anything to install them.

Built for Boost

Factory head bolts stretch and fail when you're making big power with a turbo or supercharger. Head studs don't stretch like bolts do, which keeps your head gasket sealed even when you're pushing serious cylinder pressure. The 4140 steel construction and 210,000 psi tensile rating means these studs can handle the loads that come with forced induction without pulling out of the threads or snapping.

Oversized Nuts and Washers

SpeedFactory uses oversized forged 9/16 inch 12-point nuts and hardened parallel ground washers. Most head studs on the market use smaller 1/2 inch nuts and washers. The bigger nuts and washers spread the clamping load over a larger area, which reduces the stress on your cylinder head and helps prevent cracking around the stud holes. The 12-point design also makes it easier to get a socket on the nut in tight spots.

Hex Broach and Dog Point Design

The top of each stud has a 3/16 inch hex broach cut into it, so you can use an allen key to thread the stud into your block without fighting it. The bottom of the stud has a dog point that seats into the block and preloads the fastener, which gives you consistent and accurate torquing. You're not guessing if the stud is seated properly or torqued right.

Black Oxide Coating

The studs have a black oxide coating that resists corrosion. If you're running the car in wet conditions or storing it for long periods, the coating keeps the studs from rusting.

Comes with ARP Assembly Lube

The kit includes ARP Ultra-Torque assembly lubricant. Use this lube on the threads and under the washers when you install the studs. It gives you accurate torque readings and prevents galling.

Pair with SpeedFactory MLS-HP Head Gasket

For the best sealing setup, pair these head studs with a SpeedFactory Racing MLS-HP multi-layer steel head gasket. The combination of studs and a quality MLS gasket is what you need to keep your head sealed at high boost.

What You Get

• 10 pieces SpeedFactory Racing 4140 head studs
• 10 oversized forged 9/16 inch 12-point nuts
• 10 hardened parallel ground washers
• ARP Ultra-Torque assembly lubricant
• 210,000 psi tensile rating
• 11mm diameter studs
• 3/16 inch hex broach for installation
• Dog point design for consistent preload
• Black oxide coating
• Direct drop-in replacement for OEM head bolts

Fits These Engines

• B16A (B series VTEC)
• B18C1 (Integra GS-R)
• B18C5 (Integra Type R)
• B20 VTEC (B20B with VTEC head)
• LS VTEC (B18A/B with VTEC head)
• K20 (all variants except K20C)
• K24 (all variants except K24Z7)

Does Not Fit

• K24Z7 (2012-2015 Civic Si engine)
• B18A/B with non-VTEC head
• K20C (2017+ Civic Type R engine)

Important: These studs are for B series VTEC engines and K series engines only. They do not fit non-VTEC B series engines (B18A/B, B20B without VTEC head) or K24Z7 engines. Use ARP assembly lube during installation for accurate torque readings.