Editing Chevrolet big-block engine (section)

==Generation VI==
===Vortec 7400 (L29)===
The Vortec 7400 L29 {{cvt|454|cuin|L|1|order=flip}} [[V8 engine|V8]] was a [[truck]] version of the Chevrolet big-block engine. Introduced in 1996, it was produced for five years, until replaced by the Vortec 8100. Although introduced as the Vortec 7400 in 1996, it was basically a 454 big-block with a hydraulic roller [[Cam (mechanism)|cam]], parts more suitable for use in [[light truck]]s, and more advanced technology. The engine had MPFI (multi-port fuel injection), which gave slightly more power and better fuel economy, and two valves per cylinder. The engine had a bore and stroke of {{cvt|4+1/4|x|4|in|mm|1}}, producing {{cvt|290|hp|kW|0}} at 4000&nbsp;rpm and {{cvt|410|lbft|Nm|0}} at 3200&nbsp;rpm.
It was used by Mercury Marine, named the Mercruiser 7.4 MPI and later Mercruiser 7.4 Mag. Mercury also adopted the 8.1L engine

L29 applications:
* 1996–2000 [[Chevrolet C/K (fourth generation)|Chevrolet C/K / GMC Sierra]] 2500, 3500, and C3500HD (above 8,500 pounds GVWR)
* 1996–1999 [[Chevrolet Suburban|Chevrolet/GMC Suburban 2500]]
* 1996–2000 [[Chevrolet Express|Chevrolet Express/GMC Savana]] 3500
* Mercury Marine Inboard

===Vortec 7400 (L21)===
The Vortec 7400 L21 was a [[Commercial vehicle|commercial]] version of the Chevrolet big-block engine used in the [[medium duty truck]] platform. Its design shared much with the L29 454, but with the addition of forged pistons and crankshaft, and [[Distributor|coil near plug ignition]]. It had slightly reduced power compared to the L29 454 and used a different [[Powertrain control module|PCM]]. The L21 was paired with the early 4-speed [[Allison Transmission|Allison]] [[automatic transmission]] or [[manual transmission]], depending on the application.

L21 applications:
* 1998–2001 [[Chevrolet Kodiak]]/[[GMC TopKick]]/[[Isuzu H-Series]] 4500 and 5500
* 1998–2001 P12 HD Motorhome Chassis. The Workhorse W-20 is a clone of the P12 Chassis.