Gen III+ Engine Parts


Engine Conversions

GM Gen III+ engines generally install, in and of themselves, without many special parts. But there are a handful of helpful pieces that make the conversion go better. We recommend and offer the following components.

EGR Block-Off Plug

GM 12558346, EGR Blockoff

Kit, EGR block-off, GM, 1997 C5 LS1, 1998-2000 F-body LS1, 1999-2001 Vortec

By 1998 in the Corvette LS, GM had refined their PCM programming enough to finally be able to eliminate the system that every mechanic likes to dislike: Exhaust Gas Recirculation. Because of such complete and efficient combustion, Gen III exhaust emissions had become clean enough that EGR became unnecessary. This advancement trickled throughout the GM line and by 2002, EGR had pretty much been eradicated from the GM Gen. III+ LS / Vortec series.

The EGR system can be removed from any Gen III engine by the installer without any adverse mechanical effect and as long as the their local jurisdiction allows for it. Check your local laws. The PCM will need to be programmed, which is usually and already part and parcel of any conversion.

The EGR port on the LS & Vortec intake manifolds can be easily and quickly plugged with Novak's EGR block-off kit, which includes the billet aluminum plug, special sealing ring and metric stainless fastener.

Vortec / LS EGR Plug Installed

Where legally permissible, removal of the EGR system - and its associated exhaust tubing, valve and wiring - does a lot to mechanically simplify and visually tidy the look of the installation of the earlier GM LS & Vortec engines into conversion applications.

Evaporation Purge Solenoid Relocation Kit

GM EVAP relocation kit

Kit G3EV2, EVAP relocation for GM Gen. III intake manifolds

Vortec (truck) versions of GM Gen. III+ engines feature a vertically mounted and tall EVAP purge solenoid that presents hood clearance problems for lower hood Jeeps, such as JK's, TJ's, YJ's and others.

Novak has created this kit to rotate the EVAP solenoid 90 degrees, positioning it lower and able to clear these lower hoods.

The kit includes the billet retention plate, hose adapter, o-ring, hose and clamps. Purge solenoid shown, but not included, as you will use the one native to your model of engine. Note that this kit may work with many Gen VII Big Block applications as well.

This kit is often used in conjunction with our low-profile GM Vortec engine top cover kit.

Evaporation Purge Solenoid Plug Kit

EVAP purge solenoid plug

Kit G3EV1, EVAP block-off plug for GM Gen. III intake manifolds

Where legally permissable, and generally used on earlier Jeeps without an Evaporative Emissions System (EVAP), this kit is helpful in blocking off the manifold EVAP port of GM Gen III+ and GM Gen VII 8.1L Big Block.

This kit should be used in conjunction with PCM programming to disable the EVAP purge function.

This kit is often used in conjunction with our low-profile GM Vortec engine top cover kit.

The kit includes the billet retention plate, plug, bolt and o-ring. You can use your factory rubber gasket, though it's probably optional.


Manifold Vacuum Brake Booster Adapter Fitting

Vortec LS Manifold Vacuum Brake Booster Adapter

#G3VP, Port, vacuum, Gen III manifold adapter, power brake vacuum hose

Essentially all Jeep vacuum brake boosters use a 3/8" vacuum hose. This adapter fitting reduces the factory Gen. III+ manifold vacuum port down to 3/8" for simple connection of your vacuum boost hose.

Note that some GM truck engine applications use Hydroboost brakes instead of vacuum assist brakes, and these ports will need to be drilled out on these particular engines before this fitting can be used.


Oil Level Sensor Plug

Oil level sensor plug for GM LS Oil pan

Plug, GM oil level sensor, with sealing washer, 4.5 x 2.2 x 1 inches, #2361

GM Gen III+ engines often use an oil level switch installed on the passenger side of the oil pan sump. This switch can trigger a light on the GM gauge module to warn the driver of a low oil condition. Since swaps don't typically employ the GM dash and because this switch and its surrounding guard can interfere with some Jeep driveshafts, we prefer to remove and replace them with this clean looking and tight sealing plug.


Installation is very straightforward, requiring only a box wrench or adjustable wrench. If your oil pan features a shield that requires removal for driveshaft clearance, this can be done with an aluminum-safe cutting tool (not a cutting wheel! - for risk of wheel explosion).


This Jeep's driveshaft got a bit cozy with the cast-in aluminum boss that guards the (useless in a Jeep) oil level switch. The best practice here is to properly remove the boss and the switch.