Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by Curky, May 1, 2012.

  1. Curky

    Curky Epic Member 5+ Years 1000 Posts

    After talking to my neighbor. who is also my mechanic. I am not one. If I take it off I can put it on but that’s it. Here is what I am planning at this time. It will take a little time, but here it is:
    (Keep in mind I have 2008 Silverado WT Ext. Cab V6 4.3)
    Cold Air Intake
    Leveling 2.5
    Cut off Muffler replace with pipe
    Thorndale body spacer
    Rear axle from 3.23 To 3.73 plus differential
    Don’t know where I want to go here- 295/70/17 or 305 or 315 tires
    Last edited: May 1, 2012
  2. Jeremy09LTZCrew

    Jeremy09LTZCrew Epic Member 5+ Years 1000 Posts

    The 295s are already measuring a bit over 33" diameter for the tires. With a level kit you won't want to go any bigger than that or you'll have rubbing issues. I'm no expert myself, but I've read from several posts on here and elsewhere that the body spacer doesn't actually give you anything. If I'm wrong, someone will correct me.

    Out of curiosity, why are you planning to go from 4.23 gears to 3.73? It seems you're trying to get a bit of performance from your other upgrades and particularly if you're looking at bigger tires, that won't give it to you. You'll probably get better mileage, but less low end.

    Also, don't forget to get your speedometer calibrated with the bigger tires whether you do that with an aftermarket tune or alone.
    1 person likes this.
  3. Curky

    Curky Epic Member 5+ Years 1000 Posts

    He said that is as big as I could go w/o rubbing (295)if I went any bigger we could do some cutting but I don't want to do that.
    The gears I was wrong it is now 3.23 and I want to go 3.73. My bad…
    For the speedometer he said as long as we get the right programmer that will fix that.
  4. Jeremy09LTZCrew

    Jeremy09LTZCrew Epic Member 5+ Years 1000 Posts

    Yeah, I think you'd be happy with the 295s and then not having to worry about cutting. The gears makes a lot more sense. And yeah, I assumed you'd take care of the speedo with the programmer/tune, but just thought I'd mention it. When I was 18 I got a ticket driving my Dad's truck because the Speedo hadn't been recalibrated, and he failed to tell me. I think that's the one time my dad ever cut a corner with one of his cars. He did pay for the ticket though, so couldn't really be upset.
  5. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    *If you're going to change gears and use 33s (295 70 17s, which I agree is probably the largest you can go without cutting), I'd recommend moving to 4.10 vs 3.83s. Check out this link as it will provide you some guidance on tire size and gear ratio.

    *X2 on the Throttle Body Spacer...I've read many posts in which they are NOT recommended.

    *Regarding the straight pipe, do you want this strictly for sound?

    Gear Ratio
    Last edited: May 1, 2012
  6. Curky

    Curky Epic Member 5+ Years 1000 Posts

    See that is why I posted this. I’m not a mechanic; He is and has been his whole life. He has been doing work to all my cars for 12 years. He has built some sweet race cars. He has a sweet Dodge truck and has done a lot of work to it. With that said, don’t mean he is right. This is just what we talked about.
    The straight pipe? I don’t mine the sound but I think he is trying to save me money because it has a small rattle inside. I forget what he said it was. He said it is no big deal it is just annoying.
    The gears- see it is 2WD and he said we should change the gears. That it will help with what I’m looking for. Then I asked if I could get both back tires to spin. He said it would probably be cheaper to buy the whole axle used. I don’t know why he didn’t say 4.10.
    If I say we are going 4.10. It still only cost me a case of beer.
    This is why I love it here.:great:
  7. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    Curky, you may have a locking differential already.
    Look in the glove box and there will be a sticker with a list of codes. If you have the locker it will be listed as G80, and the next G code will be your gear size. Also, check out the thread regarding the G-80 (link pasted below).
    -G80=locking rear differential
    -GT5=4.1 differential#axzz1tdUDkSZO

    Lastly, before you fully commit to a straight pipe, you may want to take off your muffler and see how it sounds. It will be very loud, all the time. I think it would be worth it to buy a muffler if you really need one.

    Last edited: May 1, 2012
    1 person likes this.
  8. 07XCSB

    07XCSB Active Member 2 Years 1000 Posts

    I 2nd the 4.10 swap. I have a 93 GMC 4.3 5spd. I did a 4.10 swap and I love it! It is a real blast to drive now. You don't have to spend alot of money to get a good sounding muffler. Look at the Thursh Welded series mufflers. Good sound and only about 35.00 dollars.

    Its sounds like a good solid plan, can't wait to see it come together. Good Luck!
  9. Curky

    Curky Epic Member 5+ Years 1000 Posts

    The code is GU5, I looked it up and it is 3.23
  10. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    Did you see the G-80 as well, in conjunction with your gear RPO code? If so, you already have your limited slip mod taken care of already :glasses:

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