Forged connecting rods Mitsubishi 2.0 16v 4G63 6-bolt 22 mm pin (Eclipse / Talon) for forged pistons

The Mitsubishi 4G63 engine (6-bolt)

Built by Mitsubishi, the 4G63 is an inline-four displacing 1,997 cc (85 mm bore × 88 mm stroke) with double overhead camshafts (DOHC) and 16 valves. It earned its reputation in turbocharged 4G63T form, powering the DSM-generation Mitsubishi Eclipse 1G, Eagle Talon and Plymouth Laser as well as the Galant VR-4, and becoming a cornerstone of engine tuning. Blocks built until roughly 1992 are recognisable by their six-bolt crankshaft — the famous “6-bolt” — prized for being stiffer than the seven-bolt block that followed.

Rated at around 195 hp from the factory, the 4G63T holds huge headroom: a larger turbo and suitable engine management let it comfortably reach 400 to 600 hp, and more still in race trim. This rise in output subjects the rotating assembly to loads that cast-steel factory rods can no longer withstand.

Beyond roughly 350 to 400 hp, the connecting rod becomes the weak link: it flexes, stretches, then fails under inertial forces and combustion pressure. Switching to 4340 forged rods secures the bottom end and unlocks the full potential of the 6-bolt block.

Forged connecting rods

Linking the piston to the crankshaft, the connecting rod turns reciprocating motion into rotation. On a built engine it withstands enormous loads every cycle: it is the first component that determines bottom-end reliability.

Forged from through-hardened steel, these rods deliver fatigue strength and stiffness far above stock parts. Designed for competition — circuit, rally, drift, drag, hillclimb or time attack — they suit a Stage 1 build just as well as the most extreme race engines.

Depending on the chosen profile and bolts, these 4G63 6-bolt rods support builds ranging from a few hundred horsepower to setups exceeding 600 hp, without ever becoming the weak point of the rotating assembly.

Technical specifications of the 4G63 forged rods (6-bolt, 22 mm pin)

Tightening torque and stretch

For assembly, the reference method is bolt-stretch measurement with a gauge, more accurate than torque alone; when in doubt, the instructions supplied with the kit always take precedence. The torque figures above assume tightening with ARP lubricant.

Technical guide

Forged 4340 steel: what is it?

4340 is a chromium-nickel-molybdenum alloy steel, shaped by forging then heat-treated. Forging aligns the metal’s grain flow and removes porosity, unlike a cast or sintered stock rod whose grainy structure is far more fragile.

The result is a tensile strength of around 1,100 to 1,300 MPa, remarkable fatigue endurance and high tolerance to thermal and mechanical shock. It is the reference material for high-performance rods: it withstands high-pressure cycles without deforming, where a sintered factory rod would give way.

Connecting rod profiles

The rod-body profile determines its behaviour under load. Two families are offered for this engine:

	H profile: an H-shaped beam, light and rigid, ideal for high rpm and moderate to strong turbo builds. It is the best weight / strength compromise for most engines.
	I-HD profile (I-Beam Heavy Duty, Manley Pro Series Turbo Tuff range): a reinforced, more substantial I-section designed to handle the very high boost pressures and elevated torque of the most aggressive 4G63 builds.

How to choose your rod bolts?

The most heavily loaded part of the rod, the bolts hold the cap against inertial forces. Every rod on this page uses 3/8" ARP bolts, available in two grades.

	ARP 2000: the versatile reference. With a tensile strength of around 220,000 psi (≈ 1,517 MPa), it allows up to roughly 200 hp per cylinder in 3/8" diameter, covering the vast majority of 4G63 turbo builds, and holds engine speeds up to 8,500 rpm. Strong, reliable and with no particular storage constraints.
	ARP CA625+: the top-of-the-range bolt. Made from a superior alloy, it accepts higher clamping loads and torque than ARP 2000 and is aimed at the most extreme race engines, with very high boost pressure and sustained high rpm.

Measuring bolt stretch

Discover the ARP stretch gauge

The brands offered

Manley Performance: an American manufacturer recognised worldwide for its forged racing rods. The H-Beam and Pro Series I-Beam Turbo Tuff ranges equip the highest-performing DSM builds and are renowned for their manufacturing consistency and reliability under heavy load.

Glossary

1) Small end 2) Small-end diameter 3) Rod beam 4) Rod bolt 5) Big end 6) Rod nut / bolt 7) Rod cap 8) Big-end diameter 9) Center-to-center

Vehicle compatibility for the Mitsubishi 4G63 engine (6-bolt)

These forged rods fit every vehicle powered by the Mitsubishi 4G63 engine (2.0L 16v turbo, 6-bolt block):

OEM reference: (set of 4 connecting rods).

Why it is the most cost-effective solution?

Given the security it provides, a set of forged rods is a modest investment. On a built 4G63, a failed factory rod almost always destroys the block, the crankshaft and, often, the cylinder head.

Fitting forged rods from the outset of a build avoids an engine failure whose cost far exceeds that of the kit. On a high-output engine, it is simply the most cost-effective insurance part.