Barra XR6 turbo build parts: what to buy and when

The Barra is the engine a lot of NZ builders end up on after owning something Japanese. Six cylinders, a factory turbo in the XR6T, a strong block and a head that flows without much help. It also has a well known ceiling, and every Barra build starts by dealing with the same part.

This guide covers what to buy and in what order, from the first head stud kit to a fully forged bottom end. One thing up front: we sell parts and rebuild packages here, not complete engines.

The short answer

• Head studs and a metal head gasket come first. That is the job that stops the failure everyone has heard about.
• Main studs and a fresh set of race bearings are the next tier, and they go in while the engine is out anyway.
• Forged pistons and rods are for builds chasing real power, not for a boost turn up on a healthy engine.
• Cams and springs go in together. Changing one without the other is how valvetrains get hurt.
• Fuel delivery and management get planned with the turbo, not after it.

Stage one: studs, gasket and the bottom end hardware

The factory head clamping is the Barra's limit. Push boost past what Ford intended and the head lifts, the gasket lets go and the coolant goes where it should not.

The ARP 252-4302 M12 head stud kit is the part that solves it. Pair it with the Cometic 1mm MLS head gasket in 93mm, which is the metal gasket for the XR6. ARP have been making fasteners in Ventura, California since 1968, and their studs are what the whole industry builds around.

While the engine is apart, the ARP 152-5402 main stud kit covers BA, BF and FG blocks. Bearings are ACL Race Series: the 6B2150H rod set and the 7M2092H main set. ACL are Australian, based in Launceston, Tasmania, which feels about right for a Falcon engine. There is also an ARP 251-2501 harmonic damper bolt kit that covers the Barra 4.0L, and it is the sort of part people order a week late.

Forged pistons and rods

This is where the build gets serious, and where the honest answer is that plenty of Barras do not need it. If your target is a decent step up in boost on a healthy engine, studs, a gasket and a good tune do the job. If the target is a number you say out loud, the standard pistons and rods are what sets the timer.

We list JE Barra BA-BF XR6 Turbo pistons at 0.5mm oversize and 9.0:1, and Manley list a 240T piston set at 92.25mm standard bore, also 9.0:1 dish, supplied with rings. Both are in the XR6 Turbo and Barra collection.

Rods split by how you use the car. The Manley H beam conrods are the traditional choice for a high power build. Manley also list Turbo Tuff I beam rods for the BA Falcon, including a version with CA625+ rod bolts, and the I beam design suits a heavy six that spends its life under boost rather than at the rev limiter. Whichever set goes in, the rod bolts get torqued to spec with the right lubricant and never reused.

The XR6 Turbo rebuild package

If you would rather not price 20 line items, the XR6 rebuild packages exist for that. The Ford XR6 Turbo package with JE pistons and Manley rods is the forged option in one order.

Our Engine Rebuild Packages page sets out the general contents: forged pistons, forged rods, a Cometic MLS or Tomei head gasket, an ARP or Mazworx head stud kit, a main stud kit where the engine uses one, and ACL Race Series main and rod bearings. The package price sits under the sum of the parts.

The machining is still yours to arrange. The block gets measured, honed and cleaned properly, and the clearances get set against the parts in the box.

Barra cams, springs and valvetrain

"Barra cams" is one of the things people search before they know what they want, so here is the plain version. Kelford list five 218 series grinds for the BA to FG Falcon six: the 218-A, the 218-B, the 218-C, the 218-EZ and the 218-SP. They are different profiles for different builds, and the right one depends on your turbo, your target and whether the car is a street car or a strip car. Ring us with the combination rather than picking on the letter.

Springs are not optional with a cam change. The KVS40 race spring set is the base option, the KVS40-K set adds retainers, and the KVS40-EXTREME set is the one for a build that revs hard. Kelford also list a VG218-24 valve guide for when the head is on the bench.

To get the timing where the tuner wants it, the KCGBARRA adjustable cam gears are the piece that makes a cam change worth doing properly. The full range sits in our Kelford Cams collection and on the Kelford hub page. Kelford Cams grind in Christchurch, New Zealand, so a Barra cam question gets answered in our time zone. If you want the longer version on picking a grind, read our Kelford cams selection guide.

Fuel, spark and wiring

A built Barra outruns its factory fuel delivery. The Radium Barra fuel rail is the tidy way to feed bigger injectors, and it sits alongside the rest of the engine hardware in the Barra XR6 collection.

On the electronics side, we stock the Haltech Elite 2000 and 2500 BA and BF ignition harness, which saves a lot of hand wiring on a standalone conversion. If you are still deciding between platforms, our Link and Haltech comparison covers what each does well in a NZ car where local tuning support matters.

What about a Barra turbo kit

There is no boxed Barra turbo kit here, and mostly there does not need to be. The XR6 Turbo came with a turbo from the factory, so a build changes the turbo, the wastegate and the plumbing rather than adding a system from scratch.

Two guides cover that decision better than a paragraph can: our Garrett G Series sizing guide for picking a frame, and the choosing turbo size and fuel system build guide for matching the two. If the engine is coming out anyway, do the studs and gasket while it is on the stand.

Where NZ Performance fits

We stock the Barra hardware in Palmerston North: ARP studs, Cometic gaskets, ACL bearings, JE and Manley forged parts, the Kelford valvetrain and the Radium rail. A Falcon build here does not sit on the hoist waiting for a container.

If you searched for a built Barra rather than parts, read engine for sale in NZ first, because the rebuild route is usually the one that ends with an engine you can trust. And for the order of operations on a big boost build, our head studs, gaskets and pistons guide is the one to read before you order anything.

FAQ

What is the first thing to do to a Barra?

Head studs and a proper head gasket. The factory head bolts are the limit on a stock Barra once boost goes up, and lifting the head is the failure people describe as a blown gasket. The ARP 252-4302 M12 head stud kit and a Cometic MLS gasket are the parts that fix it.

Do I need forged pistons and rods in a Barra?

Not for a mild boost increase on a healthy engine. Once you are chasing serious power, the standard pistons and rods become the thing that decides how long the engine lasts. We list JE pistons at 9.0:1 and Manley H beam and Turbo Tuff I beam rods for the BA to FG engines.

Which Kelford cams suit a Barra?

Kelford list five 218 series profiles for the BA to FG Falcon six, so the right one depends on your turbo, your target and how the car gets used. Springs and retainers go in with any cam change, and adjustable cam gears let the tuner dial them in. Ring us with the combination and we will match a grind to it.

Is there a Barra turbo kit for sale in NZ?

Not as a boxed kit. The BA, BF and FG XR6 Turbo already came with a turbo, so most builds change the turbo, the gate and the fuel system rather than adding a kit. We stock the engine hardware, the fuel rail and the management wiring, and the exhaust side is fabricated to suit the car.

Can I buy a built Barra engine from NZ Performance?

No. We sell parts and rebuild packages, not complete or crate engines. The usual NZ route is to pull the engine you have, send the block to a machine shop and build it with a package, which is also the version you can actually spec to your power target.