Best gears for street?

Discussion in 'Transmission & Driveline Topics' started by ratpatrol71z28, May 11, 2013.

  1. Plant Engineer

    Plant Engineer Veteran Member

    314
    61
    May 17, 2017
    Washington State
    Ive had 4.10's on just about every car I've ever built. If I wanted an economy car I'd buy a Honda.
     
  2. ZRODDER

    ZRODDER Member

    44
    8
    Sep 12, 2004
    Southwest USA
    There is a lot of good advice here, and my experience has been a 74 Z with factory 3:90s. I've ran 4:56s, but forget highway speeds for any distance. With the 3:90s i traveled back and forth from LA to OK several times and even put a bumper hitch on it from u-haul an traveled from oklahoma, to AZ to tow a 77 Z back home. It had 3:73s, but now 4:30s for stop light to stop light fun. img029(3).jpg
     
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  3. ZRODDER

    ZRODDER Member

    44
    8
    Sep 12, 2004
    Southwest USA
    Oh. That was my 74 back in 1983. It had the 3:90s, the 77 had the 3:73s.
     
  4. Trollby

    Trollby Member

    63
    1
    Apr 26, 2016
    Madison, WI
    I am running 373 on my 1970 SS with P225/70R14 (26.4") at 60MPH it is around 2900RPM or so.

    The 373 are nice gears since get the take off but not the high RPM's of the 410+
     
  5. Plant Engineer

    Plant Engineer Veteran Member

    314
    61
    May 17, 2017
    Washington State

    It does depend in tire size. I run 4.10's with a 29 inch tire . Probably roughly equivalent to your 3.73's. Mine is sized that way so I can run 135 MPH through the lights at 10 flat.

    For an automatic car the converter is going to have more to do with gas mileage than the gears will. I get 5 MPG all day long.
     
  6. ZRODDER

    ZRODDER Member

    44
    8
    Sep 12, 2004
    Southwest USA
    Sounds like my 4:56s. I did however get to make a lot of friends at the local gas stations:)
     
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  7. Trollby

    Trollby Member

    63
    1
    Apr 26, 2016
    Madison, WI
    My car came with 70R14 (14X7 rims w/ .34 offset) so I wanted to keep as stock as possible with tire size 25.5" BUT.....
    Finding 14" tires is getting harder and I got a deal on the P225/70/R14 26.4".
    I ordered the P195/75R14 that are the direct size replacement, but when I got tho the tire store to have mine installed another store came over and took my tires since they had a guy come in and ask for them (They where suppose to be held for me since I custom ordered from Firestone, not a normal stocked tire).
    So the tire shop sold me the 225/70's for same price (the cost was like $5 more per tire otherwise) and they threw in road hazard for free
     
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  8. islander2u

    islander2u New Member

    2
    0
    Nov 22, 2010
    atlanta, ga
     
  9. islander2u

    islander2u New Member

    2
    0
    Nov 22, 2010
    atlanta, ga
    47F1D6A1-0649-4059-91C2-26BED0C51D93.jpeg I special ordered my 70&1/2 Z28 with the M22 close ratio rock crusher and 4.10 posi 12 bolt. It was, for me, the ultimate combination. I ran it at the track 2-3 times a week, street raced the daylights out of it, and drove across the state of Florida numerous times to most of the tracks. With the stock F60-15 25.9” diameter tires at 32 psi I got a 50:1 ratio of Speed:RPM. So, in 4th gear....

    30 mph = 1500 rpm
    40 mph = 2000 rpm
    55 mph = 2750 rpm
    60 mph = 3000 rpm
    65 mph = 3250 rpm
    70 mph = 3500 rpm
    75 mph = 3750 rpm
    80 mph = 4000 rpm
    100 mph = 5000 rpm
    115 mph = 5750 rpm (my trap speed)
    120 mph = 6000 rpm
    140 mph = 7000 rpm (yes, it would do it)

    It would smoke the tires, in any gear, at any speed. Yes, I like 4.10s with that size tire. My current project has 3.73s, so I’ll have to get a smaller diameter tire to get me to an equivalent of a 4.10. If you’re going with a much taller tire than 25.9” I would recommend the 4.10 gear.
     
  10. Cardinal

    Cardinal Veteran Member Lifetime Gold Member

    8,243
    13
    Jun 22, 2003
    Endicott, NY
    We run 3.73's in all our SBC V8 S10's. 19 MPG on the highway.
     

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