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Help me decide....

Discussion in 'The Injection Section' started by Russell, Mar 25, 2007.

  1. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Right now I have a 2000 5.3L with approx 56 000 miles on the clock, totally complete ready to drop in, which I paid 800 for.

    I was just offered a similarly totally complete ready to drop in 2002 6.0L from a 2500 HD with approx 75 000 miles on the clock, for 800 bucks.

    Should I sell the 5.3L, and buy the 6.0L instead? I have heard the 6.0L running, and it sounds very good, ran strong and idled smoothly, no unusual noises from a cold start, no piston slapping. Truck creamed a moose, so the front end is all busted up.

    Pros:

    - More horsepower and torque, in a K25 used primiarly for towing....
    - Newer
    - Came stock with NV4500s, eliminating my problems with bolting one to an engine that never came with a standard, both in the form of mechanical road blocks, and prom stuff
    - 5.3L was run for nearly 20 minutes with absolutely no coolant due to un-seen rad damage :doah:

    Cons:

    - Don't know the maintenance history of the 6.0L
    - More mileage on the 6.0L
    - WAY worse fuel economy, lol

    Both engines are wired the same, use the same fuel systems, are identical in size, and have cable driven throttle bodies, so the work I've done on my swap already wouldn't be in vain.

    I'm thinkin I'll list my 5.3L for $1200, and let it go for a bare minimum of $1000, then buy the 6.0L...

    What do you guys think? The Pros definitely seem to outweigh the cons, lol
     
  2. Thunder

    Thunder 3/4 ton status

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    If it is going in a tow rig i would go 6.0 all the way. I would not even think 5.3
    That 5.3 was run with no coolant for 20 minutes? I would not trust it. There could be hidden damage that wont show up till you put a load on it.. Cracked head, blown gasket, scored pistons, ect.
    Fuel economy isn't too bad in the 6.0 buddy of mine has one in a 1 ton. He gets around 14 -15 mpg on the freeway towing his boat.
     
  3. Hossbaby50

    Hossbaby50 3/4 ton status

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    6.0L

    Harley
     
  4. W7NB

    W7NB 1/2 ton status

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    I would vote for the 6.0 as well. Just the tranny alone would meke it simpler, and you will get better milage towing with the 6 then lugging the 5.3.
     
  5. sled_dog

    sled_dog 1 ton status

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    umm I do not believe 6.0Ls came with a NV4500. They came with a newer Getrag transmission I believe. Don't think GM used the NV4500 in the NBS rigs. Besides which, the 6.0L, LS1, and 5.3L are so similar that whatever works for the 6.0L as far as bolting up a transmission will work for the rest.

    Pretty certain all you need to bolt up an NV4500 to a GEN III engine is a spacer for the flywheel. Search for Ryan B's conversion his First Gen K5. He is running a 6.0L with an NV4500.

    I'd look closely at both engines. Running with no coolant for 20 minutes isn't that big of a deal if the engine was cold. You won't see much of a fuel mileage difference. And any tuner worth his salt will be able to do a 5.3L tune for a manual transmission. There is nothing special about programming for a NV4500 vs the 5 speed the 5.3L DID come with. Afterall, its a manual, wtf does the ECM need to know besides Vehicle Speed Sensor signal?

    Oh and being as these don't have a PROM, it will be a full PCM you need to have programmed, and it has to be reprogrammed either way to eliminate the Anti-Theft GM built in from 98+.

    That said, a 6.0L would be more what you are looking for power wise.

    Oh and can you please bring me down the 5.3L? I wish to hell I could find either a 5.3L or 6.0L for $800. I can't even find one in need of a rebuild for that much!!
     
  6. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Yep, the early 6.0Ls did some with NV4500s, I know that for a fact :) They have a crank that is spaced the same as a typical old small block, and use a similar flywheel to the old engines, later on (03 I do believe) they switched to the same crank as a 5.3L, and used a newer Getrag like you suggested.

    Yes, I can bolt that same flywheel onto a 5.3L physically, but it is still .400" recessed, and if you put a spacer behind it with an extended pilot bushing, you solve the problem of the clutch stuff, but then your starter won't fit anymore, lol

    Only real options involve installing an early 6.0L crank and use the stock 6.0L flywheel etc, or buy yourself a 700 dollar USD conversion flywheel kit from Advance Adapters. Either way, not cheap!

    It was about -2 degrees outside when I ran the 5.3L, but the temp gauge definitely got hot. The engine had no coolant in it at all, but I was watching the temp gauge, and saw it got to almost 250 degrees, which means that it was the air between the cylinders that got that hot. It was then I suspected there might be a problem with the cooling system. The rad bottle still had some coolant in the bottom of it, but there is no rad cap, so I figured it just lost the coolant that was in the bottle when it rolled.

    The big thing about getting the PCM flashed (sorry, TPI prom stuff is ingrained into my head, lol) for a 5.3L with a standard is that it is suddenly quite custom work, and also quite expensive. Flashing the 6.0L PCM is just a matter of providing a 6.0L / NV4500 VIN number to the tuner, and getting VATS disabled.

    The difference in the programming is actually pretty significant between a standard and an auto. Esspecially with how the engine idles, holds your RPMs for you for a few seconds when you shift, or are crawling around in traffic, and fuel cut-off protocols while downshifting etc.

    And yeah, I'd be happy to sell my 5.3L to you, just gotta come drive the 3000 some miles :D
     
  7. sled_dog

    sled_dog 1 ton status

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    I no sooner posted that than I found on in Jersey less than 1 hour away for the same price, haha. Almost bought it on an impulse buy, but the guy took away the Buy It Now option(ebay auction). So I am waiting it out. Would be sweet in the 69 Firebird.

    Sounds like you pretty well have **** figured out. So 6.0L sounds like your best option then.
     
  8. 99GmcClassic

    99GmcClassic Registered Member

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    I got a 6.0 in my DD you won't regret it
     

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