Is this too much Gear for my application. Street Car

Discussion in 'Got gears?' started by mummy68, Nov 15, 2017.

  1. mummy68

    mummy68 Silver Level contributor

    It's just a spring and summer driver. Do you think it will be fine? No racing or track.
  2. YoDesigner

    YoDesigner 69 Skylark

    I think you will be fine with the 10-bolt for the type of driving you describe. If you were taking it to the track often, I would suggest the 12-bolt. On my old 69-455 I had upgraded to 12-bolt 3.08 gears but was taking it to the track. I did break 2 10-bolts over the years with that car, but I was using slicks and 4000 stall switch pitch. It would pull the front off the ground.

    Btw, I wish that 12-bolt 4:11 was near me, I need one like that for my ride.

    Hope you are getting your ride back on the road soon.
  3. 69GS400s

    69GS400s own amusement ride!

    Looks like your car is a Convert as mine is, which means HEAVY .. but if its just a cruiser with little to no hard acceleration from a stand still .. you should be all right.
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Unless you are hooking it up solid at the track on a regular basis, the 8.2 will be fine. Wheel spin is OK. 3.23 is a nice ratio, and the GP rear should have aftermarket support anyway.
  5. Eric

    Eric Founders Club Member

    I had 8.2 3.64's in my 70 GSX Stage 1 455.
    That's too much gear for the street and was a pain in the rear ( no pun intended ) while driving on the freeway.
    Changed the whole thing out to a 8.5 out of a 71, to a 3.08 posi and she still blows the tires away with ease. To me their the perfect gear and I will never change back.
    And much easier on the engine and better on the fuel too. Unless your drag racing for all it's worth, you'll love the 3.08's.
  6. Mart

    Mart Gold level member

    Put the 12 bolt 411 in AND get an O.D. trans & convertor, then you'll be happy.
    300sbb_overkill likes this.
  7. BrianTrick

    BrianTrick Brian Trick

    A 12-bolt Chevy is a good rear,but waaaay over-rated. An 8.5” 10-bolt will give you the same results without the Chevelle gods thinking they are worth gold. A stock 28-spline axle shaft from an 8.5” is actually thicker than a stock 30–spline 12-bolt Chevy shaft. How? The geniuses at Chevy decided to taper the shaft down,before the splined section. Had they kept the shaft the same thickness all the way across,they would be a very stout shaft.
    The 8.5” 10-bolt and 12-bolt Chevy have the same thickness of pinion stem,so no advantage or difference there.
    The 12-bolt has twelve 3/8” ring gear bolts. The 8.5” has ten 7/16” bolts. You can debate that until the world ends.
    With your particular application,you will be fine with an 8.2”,or the 8.5” for added insurance.
    britt'sStage 1 likes this.
  8. mummy68

    mummy68 Silver Level contributor

    Still trying to figure things out but I have a couple options. I can get a 10 bolt with 3.08's for about $400 with new axles out of a 65 Chevelle. It's clean and ready to go


    I also own a 10 bolt 8.2 non posi with 3.23 gears. I can get a yukon posi for $150 but it needs 3.31 gears or higher. and I have to put it all together and clean it up.

    How much more performance will get fro going to the 3.36 gears ccompared to the 3.08 gears. I'm young I want to do burnouts lol!!!! or at least have the option.....

    Opinions needed!!!
  9. hugger

    hugger Well-Known Member

    Not worth the swap, 373 you would feel a difference
    Mart likes this.
  10. Mart

    Mart Gold level member

    X2 .
    I went from 3.08's to 3.90's and it was just right.
    That was with the turbo 350 trans. Switched to 2004r and 4.10's, perfect compromise for street & strip & x-way.
    Dead stop burnouts? No problem! Low/ medium roll burnouts, No problem!
    Last edited: Jan 7, 2018

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