Magnus McLaren Shortblock Engine L19 Main Bolts and Head Studs



The Magnus Motorsports L19 upgrade can be purchased as a set of main bolts or head studs that are direct OEM replacements.

  • Main Bolt Kit : 10 Large Main Bolts with washers and 10 Smaller Main Bolts with washers
  • M12 Studs : 20 L19 Studs with nuts and washers

The dimensions are exactly to manufacture specifications and no adjustment to the block is necessary.  As with our other track application engine programs, we reached out to ARP to manufacture these bolts out of L19 to ensure a clamping force of over 1000psi.

These bolts are used exclusively in our 1200hp+ crate engines, McLaren M830t and M840T.

“L19: This is a premium steel that is processed to deliver superior strength and fatigue properties. L19 is a very high strength material compared to 8740 and ARP2000 and is capable of delivering a clamp load at 260,000 psi. It is primarily used in short track and drag racing applications where inertia loads exceed the clamping capability of ARP2000. Like most high strength, quench and temper steels – L19 requires special care during manufacturing to avoid hydrogen embrittlement. This material is easily contaminated and subject to stress corrosion. It must be kept well-oiled and not exposed to moisture.” –


Part Numbers

MMCENG7204-001     L19: M12 x 1.75 Larger Main Bolt (10pcs)       

MMCENG7204-002    L19: M10 x 1.5 Smaller Main Bolt (10pcs)

MMCENG7204-003    L19: M12 Studs (20pcs) with matching Nuts and Washers

Additional information

Weight 7 lbs
Dimensions 15 × 5 × 5 in
McLaren M840T Shortblock

Main Bolts Large (10pcs) and Small (10pcs), Studs (20pcs), Main Bolts and Studs (40pcs)