Switched to 3.73 gears and not loving it

Discussion in 'High Performance Modifications' started by sinnyz_me, Jul 7, 2018.

  1. G72Zed

    G72Zed Veteran Member

    Messages:
    1,016
    Likes Received:
    216
    Joined:
    Sep 8, 2015
    Location:
    Canada
    There Are 3 options for first gear in the Super Street 5spd. The 3.33, 3.06 and the most popular one at 2.89. TKO 600 is 2.87. The 5th gear was the big factor for me going to the Richmond, I use 3.73 and a 27” rear tire, .64 was to deep, and .82 was not enough, Richmond’s .77 was just right with my 3.73.
     
    dave@ztech likes this.
  2. Plant Engineer

    Plant Engineer Veteran Member

    Messages:
    383
    Likes Received:
    97
    Joined:
    May 17, 2017
    Location:
    Fort Mill SC
    I think the 3.06 first with the 4.10 gears and 29 inch tires is perfect for hard launches and the .77 final is great for highway driving not to mention a theoretical top speed north of 160 MPH. If I had short or narrower tires in Back I might feel differently. The current pro street Hoosier tires will break loose on a hard launch. The old mic keys wouldnt but the road manners of the Hoosier tires are the world of difference better. They drive like big normal street tires.

    I'm considering picking up some little bitty 325/50-15 V rated tires to use on 15 10 wheels for regular street driving and possibly changing to more of a street style triangulation style with urethane rod ends. The steel heim end 4 link setup is a great drag setup but leaves a bit to be desired for normal street use.real clunky.
     
    Last edited: May 23, 2019
  3. Francesco

    Francesco Veteran Member

    Messages:
    116
    Likes Received:
    7
    Joined:
    Jan 9, 2015
    Location:
    Drummondville, Quebec
    Im learning so much on this forum! I get all confused with these numbers you all throw out. So what is a 3.73 gear good for? Does it need a specific tire size and width for it to be optimal? How does it work? I had 295-50-15 in the back of my car and it was mental! Loved it! I don't know if that tire size was a good idea lol.
     
  4. Plant Engineer

    Plant Engineer Veteran Member

    Messages:
    383
    Likes Received:
    97
    Joined:
    May 17, 2017
    Location:
    Fort Mill SC
    Ithe depends what you are doing with it. If it's just a cruiser and you like wagon wheels it won't hurt a ring to put 22 inch wheels and rubber bands on it. If you are more the stoplight to stoplight kind of guy or like to drag race it every now and then I've always felt it's a good rule of thumb for a street car to have a transmission gear/rear end gear/tallest and widest tire combination to give an average of 30-35 MPH potential per gear. As in 30-35 MPH in first at 6500, 60-70 in second, 90-105 in third, 120-140 in fourth and if you have the power to push it that fast and have at least V rated tires 150-175 in high gear. Taller the tire and wider the more of a contact patch on the road . Short sidewalls deflect less and are better for cornering to an extent but don't work all that well for straight line stuff where you have a lot of power to hold down.
     
    dave@ztech likes this.
  5. jeff swisher

    jeff swisher Veteran Member

    Messages:
    1,252
    Likes Received:
    373
    Joined:
    Apr 26, 2018
    Location:
    Yukon Oklahoma
    I like a 3.70 gear and I have went way north of 160 MPH with a 3.70.
    And it ran in the deep 11's in the 1/4 mile.
    350" that liked to Rev.
    TH 350 7600rpm in third with 30" tire.
    That was actually 176 MPH in that old car.
    Worked very well for cruising and pulling my boat to the lake.
    NO overdrive needed.. But it may be what you get used to.
    I was cruising the highway yesterday at 4300rpm with 29.5" tall tire and 4.56 gears. Does not bother me a bit.
     
  6. DesmoEd

    DesmoEd Veteran Member

    Messages:
    1,137
    Likes Received:
    6
    Joined:
    Sep 9, 2009
    Location:
    Frisco, TX

    Now you have got me wondering if the additional 1st gear options are a newer addition. I researched 5 speed tranny's and bought the TKO for my '69 about 10 yrs ago and for some reason I don't remember them having multiple 1st gear ratios to choose from. If so, thats a welcome addition as the 2.89/.77 ratios are a nice alternative if the .64 TKO is too deep for your engine setup. I went with the .64 TKO for my Camaro as its a fairly mild hyd roller 355 with a 27in rear tire that runs clean at 2000-2200 rpm. The vette got the .82 version as its a 2800 lb car with a 15 lb flywheel and it likes to spool up and down quickly.

    The only other major difference I see is the external side linkage on the Richmond vs the TKO's internal linkage. I have not driven the Richmond but comparing the TKO to the M-20 in the Camaro and M-21 that was original to my vette is like night and day. The TKO shifts like butter compared to either of the Muncie transmissions I have had run.

    Either option will be a welcome addition vs driving around with a 1:1 final drive.
     
  7. G72Zed

    G72Zed Veteran Member

    Messages:
    1,016
    Likes Received:
    216
    Joined:
    Sep 8, 2015
    Location:
    Canada
    For reference, the 1970-71 Z/28 came with 3.73 and a 26.1 tall rear tire (235/60/15). The 72 Z's also had 3.73, and the optional 4.10, same rear tire. Back in the day going down the highway at 3K RPM with the 3.73 gave you 62.5 mph (+/-). GM did this for a reason.

    Your 295/50/15 is 26.6, only 1/2 inch difference, very close.

    Today, going down the highway at 62 mph, your an obstacle at best, hence the reason of the popularity of overdrive automatics, or 5spd manuals. Keep the 3.73 or 4.10 that was so popular back in the day, lower your cruise RPM to 2,6-2,800 and your at 80 mph/129KPH. (pending tire dia.)

    And up here in the great white north, the good gas is hitting 6$ a gallon (1.60/Litre), another reason for O.D.
     
  8. Plant Engineer

    Plant Engineer Veteran Member

    Messages:
    383
    Likes Received:
    97
    Joined:
    May 17, 2017
    Location:
    Fort Mill SC
    The side linkage really isn't a concern with the Richmond. It uses a Long (brand) shifter that is a completely different design than the old Hurst shifter. Very stout with rod ends and heavy shift rails.

    Even so a properly set up Hurst with new bushings shifts every bit as good as a internal rail shifter. It's just that the bushings wear out in a few years. The Long shifter (G Force makes them) doesnt have that problem.
     
  9. G72Zed

    G72Zed Veteran Member

    Messages:
    1,016
    Likes Received:
    216
    Joined:
    Sep 8, 2015
    Location:
    Canada
    First off, I love your rides DesmoEd, nice setups, sweet !!

    I am 99% certain that when they released (late 2007-early 2008 ?) this "NEW" Super Street 5spd that it had 3 first gear options, all other gears the same, no OD choice, only .77.

    I bought mine in mid 2008, 2.89 first. I did lots of research on this during initial build and chassis setup, drove TKO600/M22's to compare, and like you, I use a 27" rear tire with 3.73 and a 16lbs alum. flywheel. But needed to cruise at 2,500-2,800 min. rpm as the cubes are small (333) and cam in the 260 @ .50 range, and carbed.

    The only complaint with the Richmond is the high RPM 2-3 shifts, it was OK at first, but as I started to push it, the gear clash reared it's ugly head. Repaired it with new sliders and synchros, prepped the cones and so forth, but the "clashing" came back. Was going to mod it for "pro shifting" and add in CF synchros, but decided to get rid of the synchros all together, except 5th. Hope this works out!! LOL




    pic.jpg
     
    Plant Engineer likes this.
  10. Evil Twin

    Evil Twin Veteran Member

    Messages:
    175
    Likes Received:
    30
    Joined:
    Jul 10, 2018
    Location:
    Lake Havasu, AZ
    When I want economy I drive the wifes KIA but to solve your problem I'd probably swap the 3.73 for a set of 3.42 gears. It's probably your cheapest option.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.