2.8 Iron Head V6 Specs (Gen 1)

General Data: All dimensions are in millimeters Type 60 degree V6 Displacement 2.8L RPO LL2 Bore 89.0 Stroke …

3.1 Iron Head V6 Specs (Gen 1)

General Data: All dimensions are in millimeters Type 60 degree V6 Displacement 3.1L RPO LH0 Bore 89.0 Stroke …

3.4 Iron Head V6 Specs (Gen 1)

General Data: All dimensions are in millimeters Type 60 degree V6 Displacement 3.4L RPO L32 Bore 92.0 Stroke …

3100/3400 Ported Manifold Torque Procedure

The WOT-Tech Competition Manifold Set requires the following torque procedure. Failing to follow these directions may result in a cracked manifold. This is a common issue even for stock manifolds when overtightened, but is even more important with the port work that has been done. Lower Intake Ma…

Swapping a 3500 Plenum onto a 3400 Engine

The 3500 upper intake is great for the larger plenum volume and stock 65mm TB opening, but presents some issues when used on a 3400 lower intake. This is a work in progress article though anything not pictured and fully explained will at least be mentioned. Stock fuel pressure re…

Small Port vs Large Port 3100 Manifolds

GM introduced the Generation III 60V6 3.1 liter V6 in the last half of 1993 with the Oldsmobile Cutlass. In 1994 these engines replaced every Multi Port Injection 3.1 liter in GM's lineup, other than the Cavalier and Lumina which used the MPFI motors for one more year. Although the upgrades over t…

Choosing 3100/3400 Manifolds

Choosing a lower intake is fairly simple. There are date stamps on them. This blank manifold came out of a minivan and should be avoided at all costs due to the injector boss design hindering the flow. Ported underflows a stock 2000+ manifold. 00 and …

94-99 3100 Large Port Swap

Small port 3100 owners can gain a considerable amount of power and gas mileage from doing the large port manifold swap. The intake gasket kit for instance, needs to be a hybrid type for your 94-99 heads and the large port manifolds. The heads, while compatible, have a different pin locator for the i…

Using a 3400 fuel rail with a 3500 upper intake

3500 swaps and 3500 top end swaps have their own quirks to making the installation work properly, and the 3500s returnless fuel rail system is one of them. The 3100 and 3400 rail/injectors all fit the 3500 lower intake, but the upper intake has a clearance issue with the fuel pressure regulator. The…