Also known as the Vortec 7400, the L29 was the final and most modern iteration of the venerable big block Chevy. It was available from 1996 to 2000 in 2500/3500/3500HD trucks and 2500 Suburbans. Factory power rating was 290 HP at 4000rpm and torque was 410 ft-lbs at 3200rpm.
Axles
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GM Corporate 9.5″ 14 Bolt Semi-Floating Axle
The GM 9.5″ 14 bolt semi floating axle is a common upgrade for people who want to retain their 6 lug wheels and move up to something more robust than the 8.5″ 10 bolt.
The semi-float 14 bolt bridges the gap between the 10 bolt and the big boy 14 bolt FF axle. It is still a c-clip axle, but with a larger 9.5″ ring gear, bigger pinion diameter, and bigger axle diameters than the 10 bolt.
1990
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1990-1993 454 SS : 90’s Muscle Truck
Introduced in 1990 as a performance package for the C1500 shortbed regular cab pickup, the 454 SS borrowed many of the design elements from the available Sport Equipment Package and added the 7.4L big block V8 from the heavy duty trucks (along with a few other additions). Only available for 4 years, true examples they are relatively rare, but they are often copied. All true 454 SS trucks will be regular cab, shortbed, fleet side trucks with the RPO code B4U.
1988
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L19 454 : Big Block Workhorse
The L19 was available from 1988 to 1995 in 2500 and 3500 trucks, and also in the 1990-1993 SS454 C1500. The general specifications remained very similar for its entire run, other than a block redesign to to new Mark V architecture in 1991.
Axles
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GM Corporate 8.5″ 10 Bolt Semi-Floating Axle
This is the well known “10 bolt”, so named for the number of bolts on the rear cover. The majority of C/K1500 trucks were equipped with this rear axle. Not to be confused with the passenger car 8.5″ differential, or the various other 10 bolts, the truck version is significantly…
Axles
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GM Corporate 10.5″ 14 Bolt Full-Floating Axle
The 10.5″ 14 bolt full floating (full floater/FF/floater) is one of the toughest rear axles installed in the GMT400 platform. Its capacity far exceeds what most of the trucks were rated at towing and payload. These axles can be found in C/K 2500 and 3500 pickups, Cab & Chassis Trucks,…
1988
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CUCV II : GMT400 joins the Military
A rarely seen model is the 1987-2001 CUCV II, the militarized version of the civilian GMT400 platform. Only purchased in small numbers by the US military (Only number I have found in my research is around 800 units), with over 3,000 ordered by other governments across the world.
The CUCV II was a modernization of the more well know “squarebody” CUCV. Based almost directly on the civilian version, only specific changes were made for military use. CUCV II’s were not inherently more heavy duty than what was available to everyone else from their local GM dealership.
1991
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1991 Model Specifications : W/T is ready to work
For 1991, the new low-cost W/T trim was release. The W/T was a stripped down fleet side, long bed, regular cab work truck…the 4.3L V6 and manual transmission were standard. A/C and radio were not! The 454 SS was also updated with an more powerful 255hp/405ft-lb 454 V8, 4.10 gears, and a 4 speed 4L80E automatic.
1990
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1990 Model Specifications : SS454 Introduced
The 1990 model year featured a few exciting changes for the GMT400 Platform. The SS 454 package (RPO B4U) was released, combining the sport package with a host of performance upgrades including the L19 454 big block, 3.73 9.5″ rear differential, TH400 transmission, and suspension/steering upgrades.
1989
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1989 Model Specifications : The Z71 is here
The 1989 model year featured only minor revisions from the previous year. Pickup trucks still remained the only body styles available in the GMT400 platform.
Here you will find specifications and information for 1989 model year Chevrolet and GMC full-size trucks.
This includes engine ratings, drivetrain specs, and chassis dimensions.