Standards
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Ford Barra Head Studs (Australian XR6 Turbo, FG, FG-X)
The Ford Barra 4.0L inline-six turbo (Australian Falcon XR6 Turbo, BA / BF / FG / FG-X chassis, F6 and Sprint variants) is renowned for extreme high-boost capability on the closed-deck iron block. The Barra 240T (BA / BF), 270T (FG), 310T (FG-X), F6 270T, and Sprint 325T variants share the same head-bolt pattern: 14 M12 head bolts in a 2-row pattern. Stock factory TTY head bolts handle the factory 18 to 22 psi boost reliably; aftermarket builds targeting 30+ psi need stud upgrade.
TorqBolt Barra head studs (TB-BARRA-MP35N) ship as 14 M12 x 1.5 studs in MP35N (260 ksi) or Custom 465 H1025 (220 ksi). The Barra is the Australian equivalent of the 2JZ in tuner culture, and the bolt-on stud upgrade is one of the first modifications on any high-boost Barra build alongside the famous Plazmaman intake and Garrett G-series turbo.
Barra head stud installation
- Remove factory bolts in reverse pattern.
- Chase all 14 M12 x 1.5 holes in the iron block deck.
- Install studs hand-tight, back off 1/2 turn.
- Set head with new Cometic or HKS MLS head gasket.
- Lubricate threads + under-nut face with moly lube.
- Tighten in 3 stages, criss-cross from center outward: stage 1 at 30 N-m, stage 2 at 60 N-m, stage 3 at 100 N-m final.
- For 1000+ hp builds (modified turbo, race fuel): torque-angle stage 4, turn each nut 90 degrees from stage 2.
- Re-torque after first heat cycle.
Barra family fitment
All Barra turbo variants (240T BA / BF, 270T FG, F6 270T, 310T FG-X, Sprint 325T) share the head-bolt pattern, and the TB-BARRA-MP35N kit fits all. The naturally-aspirated Barra 195 / 220 (XR6 NA) shares the same pattern but typically does not need stud upgrade since boost is not in play.
Installation best practice
Achieving the design preload is as much about the install method as the bolt: lubricant matters (published torque values assume 0.13 to 0.16 friction coefficient; anti-seize or moly-disulfide reduces friction 20 to 30 percent and over-stretches the bolt at the published torque). Direct bolt-stretch measurement with an ultrasonic gauge or stretch gauge over the bolt centerline cuts preload variation to under 5 percent vs torque-only at 25 percent. Race builders measure stretch.
Re-torque after first heat cycle (run engine to operating temperature, allow to cool overnight, re-check torque) recovers preload lost to embedment at the faying surfaces. Conventional alloy-steel and MP35N bolts benefit from re-torque; torque-to-yield (TTY) bolts are NOT re-torqued and are typically replaced rather than reused after disassembly.
Alloy choice vs build budget
For street + occasional drag (target 500 to 700 hp): heat-treated AISI 8740 chromoly at 200 ksi is sufficient. For sustained 700 to 1000 hp street/strip: Custom 465 H1025 at 220 ksi or L19 race-grade at 270 ksi. For 1000+ hp drag racing or roll-racing: MP35N at 260 ksi. The bottom-end limits (rod tensile, main-cap stretch, deck flatness) become the bottleneck above this level, not the bolt.
Request a Quote
Send a build sheet (engine variant, target boost, fuel, gasket choice) and we will return a firm quote within 24 working hours. Email info@torqbolt.com, call +91-22-66157017, or WhatsApp wa.me/912266157017.
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