The Vortec 454

Vortec 7400 / Vortec 7.4 / L29 / L21

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Nov 7, 2010

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General Information

The Vortec 7400 (RPO L29)(≈454 cu in)  The L29 is what is considered a Gen VI Big Block Chevrolet (BBC) engine. Introduced in 1996, it was produced for five years until being replaced by the Vortec 8100. The L29 has a slightly revised short block from its predecessor the Gen V BBC L19 or TBI 454 or EFI 454. The L29, retained the hydraulic roller cam that the L19 had.  Above the short block the L29 was all new, with Vortec or Fastburn style cylinder heads and a brand new multi port fuel injection (MPFI) intake manifold which uses a standard Bosch style injector. These improvements jumped the power output up to 290 horsepower at 4000 rpm and 410 lb ft at 3200 rpm.

            

             L29 Applications:

             1996-2000 Chevrolet Silverado/GMC Sierra GMC Sierra Classic 2500HD & 3500 (option)

             1996-1999 Chevrolet Suburban 2500/GMC Suburban 2500 (option)

             1996-2000 Chevrolet Express 3/4 or 1 ton

 

The Vortec 7400 (RPO L21) The L21 was as a Commercial version of the L29 engine used in the Medium Duty truck platform. It shares the L29 engine block, cylinder heads and MPFI intake.  However the L21 is upgraded to forged pistons and crankshaft. It has slightly reduced hp/torque than the L29 due because it uses a different PCM with different tuning and a reduced redline.  Also some L21 engines used coil near plug (CNP) ignition systems similar to what was used on the Vortec 8100. The L21 was used with the early 4 speed Allison automatic transmission or manual transmission depending on application.

            

             L21 Applications:

              1998-2001 GMC Kodiak 4500 5500

              1998-1999 Chevrolet Suburban 2500/GMC Suburban 2500 (option)

              1998-2000 Chevrolet Express 3/4 or 1 ton

             1998-2001 Kodiak/Topkick 1998-2001 P12 HD Motorhome Chassis. The Workhorse W-20 is clone of the P12 Chassis...