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nedd some input from you guys

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by wraenking, Jul 8, 2003.

  1. wraenking

    wraenking 1/2 ton status

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    my buddy wants to throw a new 400 small block bored to 406 in my blazer. (its his, and he is giving it to me) he told me he wants to wait until i get exhaust and headers first. the engine has only 7000 miles on it, and he has over 3000 dollars into it. should i go for this? (i will be putting a 4" lift with 33's eventually) if yes, what kind of headers should i get, and what kind of exhaust. he said to get one that had a pipe going out each side. websites, prices, specific models, all would be helpful.

    thanks a lot guys


    p.s : i live in nj, so emissions is a factor.
     
  2. sdavid

    sdavid 1/2 ton status

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    If emissions is a factor, then you will have to have a legal exhaust for your year model, 1986 in your sig. And I think it will have to look stock to pass a visual inspection, but there are 50 state legal headers. Have to do some searching in the NJ laws to see what you can get away with.
     
  3. Drewminator

    Drewminator Registered Member

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    I have that same motor in my '83 K5 - a sb 400 bored to a 406. I love it. It has lots of hp and lots of torque. And let me get this straight - he is going to "give" you a $3000 rebuild and you are not jumping at it ?

    All kidding a side, unless you have very low miles on your current motor or are switching from fuel injection to a carb on the 406 I'd say go for it. Stay with fuel injection if you have it and wheel in off camber situations at all.

    You should be able to make the 406 pass. Larger diameter dual exhaust with headers will make it breath better and run stronger. Any restriction you add decrease the hp. Unfortunately, I can't help you much with your exhaust. Here in Michigan we are not tested so I'm running Hooker headers through dual exhaust in to Flowmaster mufflers. The only thing I have to consider is the db (noise) level in a state run ORV area that has a 92 db limit. Someone in your area has to run a performance exhaust shop that can give you some ideas as to what you need to do to make it pass. look into it before you start pulling your current motor as to what kind of expense you'll have ahead of you to make it pass.

    Good luck.
     
  4. Drewminator

    Drewminator Registered Member

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    Sorry, I forgot - then there is the other things you need to think about. When you start running more hp (like jumping from a 305 to a 406) you are going to be stressing a whole lot of other things. That is unless you can show a lot of restraint with your right foot. You will need to look into beefing up everything from the 406 back. The transmission, the transfercase, the drive shafts, the u-joints, and the axles - especially if your running bigger tires.

    The added hp will eventually find the weak link - and there is always a weak link ! After adding my 406 I rebuilt & beefed up both my 700R4 and my 208. My front drive shaft is stock and my rear shaft has been customized to take a bigger rear u-joint of my Dana 60, all the u-joints on the shafts and on the front axles are beefed up after market. I'm running a custom DTS Dana 60 with Moser 35 spline axles in back (after I dicintegrated my rear Corp 10 alxe shaft, ring & pinion, and Eaton Posi) and a Corporate 10 up front with 30 spline Moser inners & outers (that is until I destroy it - then it's to a Dana 60 up front). One by one the hp found the weakest link causing me to rebuild/upgrade the drive line. But my K5 gets used & I sometimes have a heavy right foot.

    In addition to your initial exhaust expense, these are some other expenses you should be thinking about/planning on in the future.

    Food for thought.
     
  5. wraenking

    wraenking 1/2 ton status

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    i appreciate the info. im sure i will be countinually upgrading as i go anyway, so that is not a factor. we recently installed the transmission that was with his 406, so the tranny should be fine. it only has about 20000 miles on it, and it has a shift kit. i will ask around about exhaust though. im sure im going to have to have cats in, so maybe that will get me to pass. ill be asking lots more questions after the swap im sure, as im sure a lot will be snapping and breaking. lol

    i have a carb right now, so not having tbi aint no ig deal. he did say we would switch out the carb because he has a "double chamber" OR SOMETHING LIKE THAT ON IT, WHICH HE SAID WASTES A LOT OF GAS. im new to wrench turning, so i look forward to learning as i go, and with you guys, im sure i cant go wrong. /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     

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