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  1. #1
    Join Date
    Nov 2016
    Posts
    8

    Default 3:73 vs 3:08 vs 3:23

    currently running a 373 gear ratio with a 350 turbo 455 engine and a 27 inch tire and im looking for a good gear that will cruise comfortably at 65 mph but still have the low end grunt. going to a 284-88h cam this weekend also. ive tossed around the idea off a 200r4 but thats not in my budget at the moment and feel the previous 2.56 gears are a bit too high any suggestions?

  2. #2

    Default Re: 3:73 vs 3:08 vs 3:23

    Your thread title almost answers your own question - I've got cars with each gear and I like them all. My Pontiac has 3.08's, it's a terrific high speed cruiser, 80-90 mph all day long and the engine doesnt mind, but still has a bit of grunt compared to a 2 series gear. My 65 had 3.23's and was still good for distance.. would drive it to the track and race all day, pulling 60 ft's in the 2.10 range. My personal favorites are 3.42's - GM used them all over the performance range for good reason, but you can still get the car from state to state. My 73 has them and with a 235-15 tire I barely notice the revs on the highway. I also put some in my 65 and with a 14 inch tire they get kind of buzzy, but also put my 60 fts in the 2.0 range. My advice is 3.23s or 3.42s....
    Rhett

    65 Gran Sport Convertible
    71 GS455 - Unconfirmed Stage1
    73 Gran Sport Stage1 4spd
    72 Pontiac Grand Ville Convertible

    71 GS455 Conv. 4spd Tribute - Sold, now a Swedish citizen
    66 Corvair Monza 140 4spd Convertible - Sold, presumed Hurricane Sandy victim

  3. #3
    Join Date
    Jun 2007
    Location
    Connecticut
    Posts
    2,966

    Default Re: 3:73 vs 3:08 vs 3:23

    to me 3.08 is the ultimate compromise gear for behind a 3 speed trans. I run them in my 79 trans am. great for a driver, drive it anywhere.

    3.23 is just that little bit sportier, I personally wouldn't like to go any further with a 3 spd trans, especially if hiway driven.

    you cant go wrong with either ratio behind a 3 speed trans.

    I am running 3.23s with 255 tires behind the th350 In my 72 skylark 455, and it drives great around town and runs low 13s at the strip right now. Hiway revs are around 3 grand at speed.
    Ken G
    www.everyday-performance.com
    or on facebook

    NE GS/GN
    72 Skylark 455Stg1 (the BS GS)
    83 Olds Cutlass (w/78 Buick 231 TURBO) PARTED OUT
    72 Skylark 350 w/ Nitrous (12.87 @ 104.79 on 100 shot) Black Mule
    "My mule dont like people laughin'..."


  4. #4
    Join Date
    Aug 2009
    Location
    Erie,Pennsylvania
    Posts
    636

    Default Re: 3:73 vs 3:08 vs 3:23

    A 3:23 or 3:42 would be fine for non-AC .If your car has AC,then run a 3:08 or 3:23. If you get the rpms up too high,the AC clutch disengages,so you would not have AC on the highway.
    Brian Trick
    thetrickfamily@yahoo.com
    814-440-3553

    70 Cutlass W31
    70 442 W30 4-spd
    71 442 W30 4-spd
    72 Cutlass Supreme 507"
    70 Buick GS 455

  5. #5
    Join Date
    Mar 2014
    Location
    Porter Ranch, Ca.
    Posts
    2,114

    Default Re: 3:73 vs 3:08 vs 3:23

    I'm running 3.42 with a overdrive trans. I was going to move up to 3.73 but after reading Brian's post
    maybe I should stick with 3.42. In So. Cal. AC is almost required. can high rpm damage the compressor clutch ?
    $$$* 1967 Buick GS 400 *$$$

    Joe M.

    1967 GS 400 sport coupe, frame off restomod BBB
    1967 Skylark sport coupe 340 peg leg. (has been laid to rest)
    1987 K5 Blazer Silverado 4x4,
    new 4 bolt main 350 , 700r4. restored for hunting only
    1999 GMC Sierra, 6.0 The work truck
    2015 Camaro 2SS, black on black. 426hp stock

  6. #6
    Join Date
    Sep 2012
    Location
    MI.
    Posts
    2,915

    Default Re: 3:73 vs 3:08 vs 3:23

    Quote Originally Posted by Mr. Sunset View Post
    I'm running 3.42 with a overdrive trans. I was going to move up to 3.73 but after reading Brian's post
    maybe I should stick with 3.42. In So. Cal. AC is almost required. can high rpm damage the compressor clutch ?

    Your good, the OP said that the 200R4 ISN'T in the budget right now. With you already having O/D, if its a 200R4 with a .67 4th gear your final drive ratio will be 3.42 x .67 = 2.2914:1 with a 3.73 would still be 2.4991:1 still doesn't = that big of a jump in RPM. GL




    Derek
    64 Skylark,401 Nailhead,ST400,3.23:1Posi
    64 Skylark,305Vortec sbc,700R4,12blt Posi 3.73,low 14s. A sbb 300 stroker planned for it.
    72 Skylark Convert. in progress, Not yet assembled 455 .020 over,70 heads with stage1 valves,gasket matched and bowl blended,transmission to be determined.
    65 Chevy Impala,4,400lbs,383sbc,700R4,3.07posi,1.80 60' foot time low 13s @101mph,15mpg city,24mpg highway

  7. #7

    Default Re: 3:73 vs 3:08 vs 3:23

    My 73 has 3.42's, and no issues with the AC at 80 mph at least..
    Rhett

    65 Gran Sport Convertible
    71 GS455 - Unconfirmed Stage1
    73 Gran Sport Stage1 4spd
    72 Pontiac Grand Ville Convertible

    71 GS455 Conv. 4spd Tribute - Sold, now a Swedish citizen
    66 Corvair Monza 140 4spd Convertible - Sold, presumed Hurricane Sandy victim

  8. #8
    Join Date
    Aug 2009
    Location
    Erie,Pennsylvania
    Posts
    636

    Default Re: 3:73 vs 3:08 vs 3:23

    What tire diameter is on your 73? A shorter tire,like a 26" will raise the rpms versus a taller tire. Good to hear that you can run 3:42's with AC in the highway. I don't have anything with AC,and I run steeper gears. Heck,I don't have anything with power brakes or power steering either. I like it simple.
    For the guys running overdrives,I generally build a 3:42 or 3:73 for the big block guys,and 3:90 or 4:10 for the small block guys.Dont take it as gospel though.
    Brian Trick
    thetrickfamily@yahoo.com
    814-440-3553

    70 Cutlass W31
    70 442 W30 4-spd
    71 442 W30 4-spd
    72 Cutlass Supreme 507"
    70 Buick GS 455

  9. #9
    Join Date
    Feb 2002
    Location
    Oakland Gardens, N.Y.
    Posts
    27,442

    Default Re: 3:73 vs 3:08 vs 3:23

    The Stage1 A/C compressor came with a bigger A/C pulley. I believe it was 5 3/4" in diameter. The purpose being to slow the compressor down so it didn't reach "belt slinging" speed
    Larry
    1998 "Fully Optioned" SC3800 Riviera
    70 GS 455 Stage1, TSP 470, 602 HP@ 5900, 589 TQ @ 4900
    TA Hyd Roller Cam, 230*/238*, 112, .544"/.577" lift, 4-7 swap
    MSD Digital 6+, Ignitionman Distributor w/MSD trigger
    THM400 with Ultimate 258mm converter, Gear Vendors OD
    AED 1000 HO Carb, 800 CFM 7042240 Quadrajet
    8.5 10 bolt, 3.73's Race weight 4025lbs.
    Best E.T. 11.54 Best MPH, 116.06
    Larrymta@verizon.net, GSCA #291
    BPG # 1063
    N.E. GS/GN Club Assistant Director

  10. #10
    Join Date
    Aug 2002
    Location
    Calgary; Alberta
    Posts
    200

    Default Re: 3:73 vs 3:08 vs 3:23

    3.08s with 225 70 14s or 245 60 15s

    3.23s with 255 60 15s

    3.42s with 275 60 15s

    This is what I recommend from my experience when looking to compromise between performance and drivability using the T350 or T400 3 speed transmission and a big block. Go up one gear with a small block.
    Own many Olds including
    1972 442 W-30 (last 4 speed W-30 built);
    1970 Cutlass W-31 auto 3.91;
    1965 442 461 cid BBO & Richmond 5 speed;
    1987 442 with 470 cid SBO 11.37 @ 119.4;
    1972 442 524 cid BBO race car 10.89 @ 122.5;
    1973 442 350 automatic black & white
    1980 GMC 468 cid BBO powered

    Past owner of a 1969 GS 400 3 spd manual trans convertible (1 of 48)
    Looking for the keeper Buick 70-72 GS 455 or a 1973 GS 455

  11. #11

    Default Re: 3:73 vs 3:08 vs 3:23

    [QUOTE=BrianTrick;2641703]What tire diameter is on your 73? A shorter tire,like a 26" will raise the rpms versus a taller tire. Good to hear that you can run 3:42's with AC in the highway. I don't have anything with AC,and I run steeper gears. Heck,I don't have anything with power brakes or power steering either. I like it simple.
    For the guys running overdrives,I generally build a 3:42 or 3:73 for the big block guys,and 3:90 or 4:10 for the small block guys.Dont take it as gospel though.[/QUOTE

    It's a 235-75-R15, so maybe 28"? But short version is that's the way Buick built and warrantied it...and I know the guy who owned it before me spent lotsa time at over 100 with the A/C on in the CA desert...and I ran 98 in the quarter an easy 30-40 times without ever throwing a belt
    Attached Images Attached Images
    Rhett

    65 Gran Sport Convertible
    71 GS455 - Unconfirmed Stage1
    73 Gran Sport Stage1 4spd
    72 Pontiac Grand Ville Convertible

    71 GS455 Conv. 4spd Tribute - Sold, now a Swedish citizen
    66 Corvair Monza 140 4spd Convertible - Sold, presumed Hurricane Sandy victim

  12. #12
    Join Date
    Aug 2009
    Location
    Erie,Pennsylvania
    Posts
    636

    Default Re: 3:73 vs 3:08 vs 3:23

    That's good to know.
    Brian Trick
    thetrickfamily@yahoo.com
    814-440-3553

    70 Cutlass W31
    70 442 W30 4-spd
    71 442 W30 4-spd
    72 Cutlass Supreme 507"
    70 Buick GS 455

  13. #13
    Join Date
    Feb 2002
    Location
    Garfield Hts, Ohio
    Posts
    4,856

    Default Re: 3:73 vs 3:08 vs 3:23

    I run 3.42's on my 71 350 GS w/T350
    245/60/15's
    275/50/15 MT DR's on 8" Buick chrome rims when going to the track
    26" or 26.5" overall dia.
    I wouldn't go any lower in gear than 3.42 without an overdrive trans.
    71 GS 350 (mine) Best so far 13.65 @ 98.84 mph
    SP3 track testing to resume in 2016!
    413 cam going away, switching to TA roller, starting again with Stage 1 and Q-Jet, then to SP3 and AED
    87 Grand National (Hers) no passes yet
    00 Monte Carlo
    2001 GMC Safari AWD
    2007 Mazda 3
    Ranch house with 4 dogs and a cat

  14. #14
    Join Date
    Feb 2002
    Location
    Maine
    Posts
    6,786

    Default Re: 3:73 vs 3:08 vs 3:23

    Quote Originally Posted by techg8 View Post
    to me 3.08 is the ultimate compromise gear for behind a 3 speed trans. I run them in my 79 trans am. great for a driver, drive it anywhere.

    3.23 is just that little bit sportier, I personally wouldn't like to go any further with a 3 spd trans, especially if hiway driven.

    you cant go wrong with either ratio behind a 3 speed trans.

    I am running 3.23s with 255 tires behind the th350 In my 72 skylark 455, and it drives great around town and runs low 13s at the strip right now. Hiway revs are around 3 grand at speed.
    I can also attest to the 3.08's. With 14 inch wheels and lower profile 245-60 tires it does not take too long to get into the power back and car will run high 12's all day. The only thing is I'd love to improve on my 60 foot times and have a set of 3.55s but I am hesitant to use them because cruising at 60-70 is absolutely perfect tone-wise and throttle response wise. Still has sick passing power at 70mph. But again, I sacrifice a little at the bottom end (although a posi probably would help that too.)
    "Sometimes the place to be is right where you are"

    Ken Mild
    Proud member of The Stepchild Nation
    69 GS400; 462ci; 430hp, 530lb.ft.
    12.90 @108.45mph - Open diff. / 3.08 / BFG T/A's
    http://www.youtube.com/watch?v=9JjGIo3V40E

 

 

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