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Chevrolet Performance 12681431

Chevrolet Performance 5.7L/350ci L31 Long Block Crate Engine with Vortec Heads for GM Trucks/Vans


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Chevrolet Performance 5.7L/350ci L31 Long Block Crate Engine with Vortec Heads for GM Trucks/Vans $1,899.99
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L31 HD Engine
  • Replaces 809-12530283
  • Vortec 64cc Cylinder Heads
  • 1996-2002 Chevrolet Express/GMC Savana (G2,G3)
  • 1996-2000 Chevrolet/GMC Pickup (CK2,CK3)
  • 1996-2000 GMC Suburban (CK2,CK3)
  • 1996-1999 GM Chassis (P3)
  • 3/4 & 1-Ton only
  • Chevrolet Performance 12681431 Details

    L31 HD Base Engine

    3-Year/100,000-Mile Warranty, some exclusions may apply 

    Fitment Notes: This engine is not intended for marine use.

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    The Chevrolet Performance Truck 350ci L31-R Long Block Assembly was designed as a direct replacement for 1996-2000 GM full-size trucks and 1996 -2002 full-size vans. This engine comes factory fresh, manufactured using the latest in high tech computer controlled equipment and are GM engineered, tested and validated to deliver smooth, dependable performance with a Limited 3 Year / 100,000 Mile warranty!


    • *1986-2000 style block, 4-bolt mains
    • 1 pc. rear seal nodular iron crankshaft
    • Powdered metal connecting rods
    • Hypereutectic pistons 9.4:1 compression ratio
    • Hydraulic roller camshaft: Int Lift .414", Exh Lift .428", Int Duration @.050" 191, Exh Duration @ .050" 196, Lobe Centerline-111
    • Vortec cylinder heads - 64cc, 1.94'' intake valve, 1.50'' exhaust valve
    • Balance: External Rear, Internal Front
    • Also includes: Oil pan, timing cover, valve covers, harmonic balancer

       JEGS Easy Kits are designed by JEGS high-performance racing professionals to help you get all the performance parts you need for your race car, hot rod or truck.

      GM Warranty

      Note: *Service engine block contains SAE threads. When used for 2001 and newer vehicles, must also use 2000 model year starter/transmission/engine mounting bolts.

    12681431 - GM Goodwrench 1996-2000 Truck 350ci L31-R Long Block Crate Engine is rated 4.9 out of 5 by 11.
    Rated 5 out of 5 by from Can’t beat the price Installed in my truck with 245,000 miles. nothing but praise for this motor. I couldn’t rebuild mine and have a 3 year limited warranty, this is a great value for your hard earned dollar. I did have an issue with the trucking company tipping the crate over. I signed off on it with the provision there was no time to properly inspect the motor. After getting motor to my shop every thing was ok.
    Date published: 2018-10-28
    Rated 5 out of 5 by from Good motor to upgrade. 325 hp Bought this motor for my 91 Chevy ex cab half ton.about 7 yrs.ago.have 35,000 mi.on her and runs excellent. Wanted to upgrade for more power I use my truck to pull a little toy hauler.19foot. And to NOT to have to put additives in the oil because of flat tappet cam. L31 is roller cam. And the additional HP.with the vortex heads.you can message them a little ..and cut the valve guide down put new seals and springs. Then you can put a little bigger cam in. The L31 also has over 9 to 1 comp. Then I sent my throttle body to Morris machine and the bored out for more air and put a adjustable fuel pressure regulator on. And set it on a edlebrock intake. Cleaned up ign.with MSD. Some true dual exhaust. Don't get me Rong it's NOT a race truck.but I went from 180hp.which was stock for 1991. To 325 to 360 it's a happy truck.that fits my purpose very well and it's paid for. Bought most all the parts through JEGS always great to do business with. And I got a new chip..
    Date published: 2018-08-17
    Rated 5 out of 5 by from great got this to replace a 172K mile motor and put it in my toy, run great, purrs like a tiger !
    Date published: 2018-04-06
    Rated 5 out of 5 by from Flawless I purchased for my 99 suburban to replace a 300k L31 vin code R. Went in smooth no issues started first turn of the key. I have 500 miles on it just did a oil change zero issues. This is my 2nd motor I have purchased both are awesome other one has 15k miles on it. These are brand new not rebuilds and I highly recommend this motor
    Date published: 2017-10-25
    Rated 5 out of 5 by from 1996-2000 Chevy 5.7 4-bolt Installed in my Chevy Silverado 3 weeks ago and it's running like a champ. Super satisfied with this purchase.
    Date published: 2016-11-03
    Rated 5 out of 5 by from Very Happy with service and product. There were a couple issues with initial purchase approval but there was good communication with "real people" that made it all work out. The engine arrived VERY well crated. It was put in the truck and has been running perfectly every day for last couple weeks. Mechanic was so impressed he is recommending others to buy from JEGS.
    Date published: 2015-02-19
    Rated 5 out of 5 by from Great Products I purchased this L31-R 350ci long block for my 1998 Chevy k1500 Z71 4x4. I was very pleased with the packaging. Since i don't have the vortex on it and being a high performance guy i was a little disappointed with the output horse power with my truck being a 4x4. other than that, i'm pleased with the engines smooth running and dependability. Over all very happy with my purchase. Thanks Jegs.
    Date published: 2015-01-06
    Rated 5 out of 5 by from fast service great product,driven everyday we had it in three days installed it ,started with no problems. it is driven everyday in a delivery truck Thank You Jegs for a great product
    Date published: 2014-12-28
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    Is this a R code or 4 bolt main engine?

    Asked by: 38Mike
    This is an "R" code engine with 4 bolt mains.
    Answered by: Rusty B
    Date published: 2018-12-03

    What flywheel should i use for this L31-R  and a 700R4 transmission. i am puttin this in a 91 gmc truck but there is a gap about 3/8 to half inch between torque converter and flywheel. is there a flywheel i can use for this application or do i need spacer

    Asked by: Ocl23
    Push the converter all the way into the pump. Measure the gap, should be 3/16". If more, subtract, 3/16" from total gap, that is the exact amount of washers to use. Install bolt's & washer's, if needed & push forward to flexplate & tighten as usual.
    Answered by: Kenny U
    Date published: 2018-11-26

    Would this engine fit my 83 caprice classic ? Im looking to switch to a v8 carbuerated

    Asked by: Classics4life
    Not without a lot of work, this engine would be a better fit - https://www.jegs.com/p/Chevrolet-Performance/Chevrolet-Performance-350-290-Base-350ci-300HP-Crate-Engine-Package/755609/10002/-1
    Answered by: Rusty B
    Date published: 2018-11-02

    Will this motor work for chevy 96 k 2500 with the spider injectors on a manual 5 speed

    Asked by: Jjohnson
    Yes, this should work depending on the intake manifold you are using.
    Answered by: Rusty B
    Date published: 2018-11-02

    I’m looking to replace the engine in my 2000 GMC Yukon Denali. If I install it myself, does that void the warranty? If it does, I want to use this 4 bolt main engine but need more torque. If I changed the cam, would the computer operate properly? 

    Asked by: Draggin71ss
    In order to use the GM warranty a GM dealer will need to be involved with your project. You can change the cam, but that will void the warranty and you will need to tune the ECU to make it perform properly.
    Answered by: Rusty B
    Date published: 2018-11-01

    Will this engine work with mechanical fuel pump as delivered for my 86 Silverado c10, if not what engine like this will work. Thx!

    Asked by: Bryant5
    This engine does not have the fuel pump lobe on the camshaft so it will not work with a mechanical fuel pump
    Answered by: Rusty B
    Date published: 2018-10-22

    If I buy this engine...what is the biggest performance cam you guy's recommend for it?

    Asked by: z28zack
    Changing the cam will void the GM warranty on this engine. Unless you are upgrading the intake and EFI system a cam change will not work well.
    Answered by: Rusty B
    Date published: 2018-11-05

    Will this work for a 79 corvette?

    Asked by: FredP123
    No, you will want a 2 piece rear main seal engine if you want to keep all of your original accessories. This is an option - https://www.jegs.com//i/Chevrolet-Performance/809/12681429/10002/-1
    Answered by: Rusty B
    Date published: 2018-10-18
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