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5.3 ls1 engine swap?

Discussion in 'The Garage' started by moturbopar, Jun 19, 2005.

  1. moturbopar

    moturbopar 1/2 ton status

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    Hi all, I have stumbled upon a 5.3l vortec (ls1) for CHEAP!!! And I am thinking of purchasing it to put in my blazer. currently I have a 330hp 350 crate motor with low miles, it runs well but would like fuel injection. Since I can get this engine cheaper than swapping on efi for the 350 It sounds like it might be a pretty good option.I think with a good cam and headers the engine should perform pretty close to the crate 350. Oh, it come complete with harness and all accessories. Has anyone here done a swap similar to this, any major surgery neede for this swap? Anyone have an idea of what a used( less than 20,000 miles) 330hp vortec headed 350 would be worth, complete with performer, carb, headers, ready to run?
    Thanks
    Shawn
     
  2. sled_dog

    sled_dog 1 ton status

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    I'd do it personally, but thats me. Peterson's did a series of articles about swapping a 6.0L into a K5 Blazer. Requires frame modification, as well as engine crossmember mods, if my memory is serving me right. But personally it would be worth it. I'd really like to build myself another K5 with a 6.0L in it.
     
  3. zcarczar

    zcarczar 1/2 ton status

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    4 wheel & off road did the swap your talking about, tells everything that you need to do. I cant remember what month its in though. But you will need new motor mounts, either modify, or build a new engine crossmember, new exhaust, new flexplate, or flywheel, your trans will bolt up though, minus one bolt, and some other misc. things of course, but thats the basics.
     
  4. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    Unless you really want it, I'd avoid it. I'd go after a 6.0L though. Or a 5.7L.

    The numbers aren't very impressive.

    By the way, what you're looking at is a LM4 or LM7 or maybe a L59. I doubt you've got a LH6 (displacement on demand). The 5.3L motors are similar to an LS1 but a far cry from an all aluminum 346ci engine which is what RPO LS1 is.
     
  5. burbBoy

    burbBoy 1/2 ton status

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    The anti theft issues in this swap are tough to get around. Best option is to buy a harness from painless or other similar places. The engine wiring is less stand alone then you think.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Were these some of the engines that had the (potential) piston slap problem?

    Not bad engines I'm sure, but I know for awhile there were quite a few people that had the piston slap issue, and GM apparently was trying to skirt the issue.

    If you can't hear it run, and the 5.3's ARE one of the engines that could potentially have this problem, I'd be leary of buying it. Thats just me.

    Do a search on google about piston slap on those engines, you'll turn up various stories about it. I haven't looked into it in a year+, so there might be new info out there.
     
  7. drbwell2000

    drbwell2000 Newbie

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    I recently put a 5.3L in an '84 K-5 Blazer. It was an experience to say the least. It is running great, but I've still got some odds and ends to take care of before I'll be running up and down the road. It had a 305 in it prior to this, and the difference is amazing. I BARELY hit the gas while in drive, and the back tires spun over in the garage with the brakes to the floor. That may not sound like much to some, but when you consider what the 305 with a 4 barrel QUADRA-CRAP would do.... well I think you'll understand why I was impressed.
     
  8. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Yo.
    I've done several vortec engine conversions. I slammed an '04 6.0L in both my K5 and my flatbed. We're currently working on installing 4 different GenIII engine swaps now at pacific fab. A 5.3, 6.0, 5.7 LS1 and a 6.0 LS2.
    Depending on the vehicle you can either build adapter plates for the motor mounts or you'll be building a whole new crossmember around the vortec motor mounts.
    The engine is wider and more set back so the exhaust might hit the frame and the heads/valve covers might hit the firewall. Most everything has required clearancing in the frame and firewall to leave the tranny-tcase where it is.
    Reflashing the computer and reworking the harness is the toughest part especially to get around the anti theft system.
    Check out pacificfab.net we can hook you up with complete turnkey engines, or I can rework your harness (if you get most all of the wiring) and have your computer flashed, and test run it all.. for a reasonable rate to make it all work when you start looking into having that end of it done.
    What year is the engine you're looking at getting? If its the earlier style with a throttle cable its an easier swap. If you get the drive by wire setup, its a lot tougher to get that working, but i've successfully got several of these setups working now and i've got it down. :thumb:
    PM me if you have any specific questions. :wink1:
     
  9. beastofablaze

    beastofablaze 1/2 ton status

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    Why... with a little tweakin the 5.3's will scream... with a blower, exhaust, and the right fuel map the'll put down 420 ft lbs to the rear wheels.... Even without the blower some good heads afrs or darts and the thing will fly.

    What are the stock numbers on those things anyway.
     
  10. misterfnygy

    misterfnygy 1/2 ton status

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    check out ls1tech.com they have a great forum over there that includes engine swaps and such. I have the 5.3 in my DD- flashed the prom, cat back and air cleaner. It goes pretty well and I still get 15MPG to and from work
     
  11. drbwell2000

    drbwell2000 Newbie

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    I found that the wiring harness and the computer flashing were the easiest mods. The fuel pump, delivery, and return along with all the other mods were the toughest for me. I bought a wiring harness from Painless... VERY EASY! I had my computer flashed and reconfigured so I could run my TH350 at PCMS4less. I removed the engine crossmember and bolted it to the underside of the frame. That allowed me the clearance I needed for the oil pan. I had to remove some of the frame edges to allow clearence for the exst manifolds. I had to move my entire drivetrain forward almost 3" to get everything to fit to the engine when using advance adapters engine mts. I'm not sure how this will affect my weight distribution. I believe the new engine is light enought to offset the move. I had to move the tranny shifting mech and shorten the t-case shifting rod. I had a new rear driveshaft made and my front one shortened. The fuel pump and the new lines were very challenging as the FI system requires 55-62 psi.(I can't remember if those are the right numbers, if not very close.) I ran new alum 3/8 line from the pump all the way to the engine compartment with a short high psi braided line from there to the fuel inlet on the engine. I could've used the stock 3/8 metal, but it would've had more joints in it than I wanted. I only gave 1275 for my engine with all the accessories and computer with 65k miles. That's the only reason I went this route. A 350 would've been MUCH easier, but the 5.3 is something that most people don't have in a K5. The turn-key start is GREAT.
     

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