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Thread: 8.1L 496 pass emissions for 5.7L TBI?

  1. #1
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    Hey I need to find out if a new 8.1L big block 496 will pass emissions for my 95 GMC Sierra with the 5.7L 350 TBI engine. That is a lot more cubes and with atleast cam, intake, exhaust probably more I need to make sure it will pass. I have a chance to pick up the 8.1 with 5k miles on it for under $1500. Please let me know what you think ASAP! Also has anyone in here sucessfully swapped an 8.1 into an 88-98 truck? Is it the same as the 6.0?

    Thanks,
    Mike

  2. #2
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    <div class='quotetop'>QUOTE(Jewmont3 &#064; Apr 6 2006, 07&#58;25 PM) [snapback]49514[/snapback]</div>
    Hey I need to find out if a new 8.1L big block 496 will pass emissions for my 95 GMC Sierra with the 5.7L 350 TBI engine. That is a lot more cubes and with atleast cam, intake, exhaust probably more I need to make sure it will pass. I have a chance to pick up the 8.1 with 5k miles on it for under &#036;1500. Please let me know what you think ASAP&#33; Also has anyone in here sucessfully swapped an 8.1 into an 88-98 truck? Is it the same as the 6.0?

    Thanks,
    Mike
    [/b]

    P.S. I forgot to ask if the T56 will bolt up to the 8.1L 496? I am guessing yes if the T56 bolts to the 6.0 and the 4L80 bolts to both the 6.0 and 8.1 but just wanna make sure...

  3. #3
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    I don&#39;t see why it wouldn&#39;t as long as you keep all of the emmissions stuff intact when you do the swap.

    [1/8 mile E.T. - 8.23 @ 82.86 mph w/1.82 60&#39;] &#39;98swb,4/6drop,20"RozziDeeps on 275/40ToyoProxes &#39;98LS1/4L60E,TRCheaTR cam,Ported TB,Billet MAF ends,MSD8.5 superconductor wires,S&P midlengths,&#33;EGR,&#33;cats,2 1/2" true duals w/X-pipe,Dynomax Ultraflows,TCI 3000,billet servo,TCI deep aluminum pan,3.73&#39;s w/Auburn posi; Eclipse CD, Rockford 6 1/2&#39;s, Memphis 12&#39;s, Punch 200 ix, Punch 500x

  4. #4
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    <div class='quotetop'>QUOTE(Jewmont3 &#064; Apr 6 2006, 06&#58;25 PM) [snapback]49514[/snapback]</div>
    Hey I need to find out if a new 8.1L big block 496 will pass emissions for my 95 GMC Sierra with the 5.7L 350 TBI engine. That is a lot more cubes and with atleast cam, intake, exhaust probably more I need to make sure it will pass. I have a chance to pick up the 8.1 with 5k miles on it for under &#036;1500. Please let me know what you think ASAP&#33; Also has anyone in here sucessfully swapped an 8.1 into an 88-98 truck? Is it the same as the 6.0?

    Thanks,
    Mike
    [/b]
    This depends on a lot of things...... Does your state do underhood checks or just tailpipe sniffer? Will you be swapping all the 8.1 smog gear along with the engine? Do you have to bring swaps to referree stations or can you get a smog check done at any local "smog hut"? All things being equal and if you swap everything over complete, your newer model motor should have no problem with meeting &#39;95 smog tail pipe standards. But if you have a state that is very picky, a big block swap can raise some eyebrows.....
    Oh yea, once you swap cams, only the sniffer will ever know... so if you have a strict emmisions state you can&#39;t go wild with the cam.

    The 8.1 is nothing like the 6.0. The 6.0 is a small block and the 8.1 is a big block. Different mounts, exhaust, accesory drives, etc., etc.

    I too suspect you could bolt up a t-56 if you put a flywheel on it (the 8.1 is internally balanced, do NOT use a 454 flywheel on it)

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  5. #5
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    I did the smart thing, which I should have done in the first place...I called the garage I use to get my stickers. I dont have to pass for my 95 engine. You can put any newer engine in a vehicle you want but you just have to pass emissions for that year engine. So I should be all set in that respect. I just need to find out if I can deffinately attach a T56 to it before wednesday.

    Has anyone in here swapped in an 8.1L 496 yet?

    thanks,
    Mike

  6. #6
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    Did you ever end up doing the swap?

    Very curious whats going on with it.

    Just wanted to shoot this thread back up to the top?
    99 C5 cam/boltons 400rwhp
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  7. #7
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    <div class='quotetop'>QUOTE(stngh8r &#064; Aug 28 2006, 01&#58;58 PM) [snapback]62750[/snapback]</div>
    Did you ever end up doing the swap?

    Very curious whats going on with it.

    Just wanted to shoot this thread back up to the top?
    [/b]

    Nope I didnt. And I went to the shop that does my emissions and talked to the owner. He told me it has to pass for the 5.7L 95 emissions no matter what I put in. So now I am confused because I get a different answer from every different person I talk to. I emailed the registry of motor vehicles and asked the question. They said it has to pass for the weight of the vehicle whatever that means. I sent an email back with more specifics so we will see what they say. I am hoping some more people do this swap. It would be a quick and cheaper in the long run way for me to get what I want for power out of the engine I swap in. If i can put the 6 speed on it I wont get any worse mileage then I do right now I dont believe.

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