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Thread: ls3 swap??

  1. #1

    Default ls3 swap??

    has anyone seen or heard of an ls3 swap into a silverado??? if so can you point me in the direction to of where you saw it or heard about it... just trying to figure out if i will have to get different motor mounts and wiring harness
    2000 single cab short bed 1500 w/ 6.0 vortec maxx swap from a 2006 2500, custom intake, slotted brakes, shorty headers, 8mm wires, electric fan, strait piped, 4.5 inch lift, asp pulleys, true dual through body exhaust, built trans w/ shift kit, custom tune ... 320rwhp

  2. #2
    Sr. Engineer
    Join Date
    May 2009
    Manitowoc, WI


    Do a search on google for LS1 to LS3 swaps, tons of information that should all apply to your swap. You won't need new motor mounts, the engine should bolt in place of yours since its still an LS-series engine. Wiring depends how much of your current engine you want to use, if you're going to run your existing intake manifold, throttle body, accessories, transmission, etc then you should be able to reuse your wiring harness with the addition of an adapter box that lingenfelter makes for the crank and cam sensor differences (runs about 250). If you want to use everything out of an LS3 vehicle, then you may need to start cutting up the harness to make things work..

  3. #3


    The LS3 has a aluminum block and I believe the motor mount bosses won't match up to truck mounts, so you'll have to play with the motor mounts, you will need a truck oil pan and oil pick-up. You front a/c, power steering will have to be modded if you keep the LS3 intake. Wiring harness will also need to be modded. I would just bore and stroke your 6.0 V/Maxx.

    2005 Chevy Silverado Z71 Crew Cab
    6" Skyjacker lift w/Edlebrock dual front remote resoviour shocks, single rear remote. Rancho skid-plate.
    17" x 9" M/T Classic Lock Wheels, 35" BFG A/T or M/T tires
    4.10 PercisionGears w/factory locker, T/A Performance rear-end cover
    Banks CAI intake, ported throttlebody, JBA coated headers, over-sized Magnaflow cats, Magnaflow cat back exhaust, Diablo tuned
    B&M aluminum deep transmission pan
    Warn brush guard w/Warn 9.5 XP winch, PIAA bulbs, Line-X bedliner, AWS Black tool chest, Extang tonneau cover
    Weather Tech floor mats
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    One black Lab in rear seat.

  4. #4


    building this motor is what ive been debating on... since this is my only vehicle im looking at being able to swap one in... either by the doing the ls3 swap thats fully assymbled making 480hp or by finding another block to build up instead. Im not looking to go nuts on the build, theres a shop near me that has a stock 5.3l with 240k making 600 to the wheels from a twin turbo kit and upgraded fuel system. There truck has been running for about a year like this.. So if i put forged internals into a stock 6.0l block i would be making 600 or more to the wheels with a good single setup

  5. #5
    TRPLXL2's Avatar
    Join Date
    Jan 2009
    Norwalk, Ohio
    Blog Entries


    I am curious as to why an LS3?

    I have been looking at my local junkyards for one out of a wrecked SS, and the cheapest one I came across was $12,000 for LS3 and 6 speed trans with 13,000 miles on it. I personally think you'll be better off with the 6.0 anyways, go with an LS7 and be done with it lol! J/K

  6. #6


    I would like more info on this also I bought a 6 litre to build and put into my 02 WS6 so Ill have the stock ls1 out of the TA with half the miles my 5.3 has
    I will swap the intake and oil pan onto the ls1 my biggest question is will the computer have to be re tuned?

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