Gear Possibility

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by jcgafford, May 16, 2013.


  1. jcgafford

    jcgafford Well-Known Member

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    Just wanted some opinions on a cheap nearby gear upgrade for my car. Totally bone stock 1992 gt vert, 2.73 gears in it now. As i understand it the "upgrade" from ford at the time was 3.27 gears. I found a set of ford 3.27 gears ten minutes away for $35 in excellent shape. Worth it or move on to the 3.55 gears i was planning. Looking for pros and cons here. Not a race car just a fun summer driver when its finished.
    #1
  2. 88LX5.Oh

    88LX5.Oh Advanced Member

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    3.55's are awesome. You'll notice more of a difference by going with the 3.55 than with the 3.27's
    #2
  3. reldla1996

    reldla1996 Member

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    327's would be a nice improvement over the 273's, but why settle for less than your heart desire unless the extra $100 or so is really a deal breaker. 355's are an excellent street gear.
    #3
  4. jcgafford

    jcgafford Well-Known Member

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    so the jump from 327 to 355 is pretty significant? the $100 isnt a deal break at all just saw something local that was "stock" and the price was good.
    #4
  5. mikestang63

    mikestang63 Mustang Master

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    stick or an auto?

    IMO it is not worth the expense, effort or time to go to 3.27. For a stick, the best all around gear for a DD is 3.55. Autos need more gear and a 3.73 or even a 4.10 is the choice. Make sure you also change the corresponding speedo gear or your speedometer will be off.
    #5
    ratio411 and 2000xp8 like this.
  6. jcgafford

    jcgafford Well-Known Member

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    auto, this is a summer cruiser for me. trips up north on the highway and just tooling around. i know i don't want the 2.73 gears but am leary on 3.73 and am flat out against 4.10's. 3.55 seem like the perfect all around gear from what i have read but ford used the 3.27 in verts. i can remember back in the 90's when these things were new that my buddys stock vert seemed "fast". guess i actually do fear the gear and while i dont want whats in there now i surely dont want what most guys are throwing in to go to the track. for 35 bucks if the difference is positive i will throw the 3.27 in there. guess i am still on the fence. i have also read about problems with the speedo gear being eaten up with the higher gear combos. any truth to that?
    #6
  7. Gearbanger 101

    Gearbanger 101 we love us some gays up here Super Mod

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    I guess that all depends on perspective. I personally feel the 3.27 gears are better for an all around driver. Zipping through the power band is fine for the first couple of gears, but I'm of the opinion the a taller gear makes better use of the 5.0L torque curve. These engines start signing off at around 4,800RPM and are pretty much done by about 5,500RPM. For a nearly stock engine, keeping the engine within that RPM range as long as possible will net you the best combination of performance and efficiency.

    Although I will admit, mileage gains between 3.27's and 3.55 or 3.73's are minimal, but then too are the performance gains. I personally spend only about 5% of my driving time in an RPM range where lower gearing is going to be of any advantage, so I prefer to spend the other 95% of my driving in a more cruise friendly RPM.
    #7
  8. jcgafford

    jcgafford Well-Known Member

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    right, i want to cruise without high engine noise yet still not get passed by a civic with nothing left when i mash the pedal.
    #8
  9. 2000xp8

    2000xp8 Mustang Master

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    If you want fun in an auto go for the 4.10's.
    When you mash the pedal, the car will downshift and you will have plenty left unless you are racing above 125mph, in which case if you have problems with a honda civic, your problem is much worse than gears can fix.
    #9
  10. mikestang63

    mikestang63 Mustang Master

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    Here you go. This site will show you the difference in gears

    http://mr5oh.tripod.com/gears.html

    In O/D
    with 3.27 you'll be around 1800 rpm
    with 3.73 you'll be around 2200 rpm

    I wouldn't fear the 3.73's. In fact , that is my next swap. It will really make your AOD much more enjoyable and actually help it during city driving as you won't be lugging around . Go to the Steeda site and get the proper speedo gear. 83-89 automatics have a 7 tooth drive gear and 21 tooth would be correct for 3.73. But 90-98 AOD's have an 8 tooth drive gear, which calls for a 23 tooth speedo gear.

    http://www.steeda.com/store/steeda-speedometer-recalibration-gears-for-ford-mustang.html

    392-STE-17271-J - Automatic 8-Tooth 3.73 Ratio / Black 23 Speedo Gear - $16.75
    #10
  11. reldla1996

    reldla1996 Member

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    That's pretty cool, that's my son's web site you just cited.... I've run 373's in mine for a long time, and not had any issue with chewing up speedo gears. A 327 will have 20 percent more torque than a 273, while the 355 adds another 9 percent; pick your poison....
    #11
  12. jcgafford

    jcgafford Well-Known Member

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    chart makes the difference look minimal. hmmm...
    #12
  13. RangerJoe

    RangerJoe Advanced Member

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    I might know a guy who has a used set of FRPP 3.73 gears for sale over in the classified section....... ;)

    Joe
    #13
  14. mikestang63

    mikestang63 Mustang Master

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    Great! Buy your son a beer for me. He put together a nice site that I have referenced many times. IMO the OP should take a ride in someone with an AOD and 3.73's and he'll be sold.
    #14
  15. jcgafford

    jcgafford Well-Known Member

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    gonna try to make that happen. had some really convincing advice to go 373 earlier. plus per the chart the rpm difference seems minor.
    #15
  16. cleanLX

    cleanLX Founding Member

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    I too would recommend 3.73's for your application.
    I went 4.10's due to my track goals and love them for that, but the 3.73's were more comfortable out on the highway.
    If it's just a play car, and you don't do a lot of long 80mph highway trips, you may want to consider the 4.10's.
    I actually got better mpg with the 3.73's than I did with the stock 3.08's.
    Take care.
    #16
  17. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    Been there and done that! With success! :nice:

    Do the 87-88 T-Bird Turbo Coupe rear end swap!

    Auto trans 87-88 Tbird Turbo Coupes come with 3.73 gears and manual Turbo Coupes come with 3.55 gears. Cost is $125-$300 for the rear axle. Add another $100-$200 or so to complete the brake upgrade.

    I choose 3.55 since I do more highway driving. Both ratios have 10 5/16" disk brakes with vented rotors as standard equipment.

    It takes 2 guys the first day to get the old rear end out and the new one bolted in place. It takes 1 guy another whole day to do the brakes.

    You will need a several sets of fittings, I recommend that you get them from Matt90GT's website, http://home.comcast.net/~mjbobbitt/mustang/page5.html. Read Matt's instructions thoroughly, everything you need to know about the brakes is all there. You need to be patient and follow all the internal links, and there are many of them. You will need 2 fittings in the rear to adapt your old brake tubing to the TC disk brakes. The fittings go between the steel tube and the caliper brake hose. You will need another set of fittings to make a 2 port to 3 port adapter. To make life simpler, just buy the kits from Matt. You could piece them together, but it's not worth the time unless you work at an auto parts store with all the fittings ever made.

    You will need to drill the quad shock mounting holes 2” below the holes drilled for the Turbo Coupe mounting points. The bolts are metric, so don’t loose them or the nuts. A 15/32” drill should be about the right size unless you have access to metric sized drill bits. Going without quad shocks is not an option.
    When you install the axle assembly you will need to leave the bolts for the control arms only finger tight. Once the axle and all the control arms are in place, put jackstands under the rear axle and under the front A arms. Level the car as best you can while it is on the jackstands. Then and only then tighten down the control arm nuts and bolts to the factory specs. This assures that there is no preload to position the axle up or down, it is preloaded to normal driving height.

    You will need a proportioning valve, Summit has one for $40 + shipping.
    You will need a kit (FMS makes the part) to gut the stock proportioning valve, Summit also has that, about $10.


    You will need a new master cylinder, see Matt's site and make you choice. I used a 94-95 Mustang master cylinder. Note that rebuilt 94-95 Mustang master cylinders do not come with a reservoir. That means a trip to the junkyard and some more money spent.

    Your brake pedal may be very hard and almost impossible to lock up the brakes. I had to replace the front calipers with 73 mm calipers from a 91 Lincoln Mark 7 to get the braking performance up to par.

    Bleeding the brakes will require 2 people and some coordinated effort. I don’t recommend using you wife or girlfriend to pump the pedal – they get offended when you yell at them. I used a homemade power brake bleeder constructed from a garden sprayer and some fittings from Home Depot. It cost about $25 and was worth every penny. See http://forums.stangnet.com/showthread.php?p=6143048 for details and pictures.

    See http://www.mustangcentral.net/tech/brake.html for help with the emergency brake. The red words link to some very useful photos on how to modify the handle. The stock setup tends to lock up and not release properly.
    All in all I have been very pleased with the results.

    Turbo Coupe axle swap parts list:
    87-88 T-Bird Turbo Coupe Rear axle
    94-95 Mustang Master Cylinder with reservoir
    Brake line Adapter fittings http://home.comcast.net/~mjbobbitt/mustang/page5.html.
    3 line to 2 line brake fitting kit http://home.comcast.net/~mjbobbitt/mustang/page5.html..
    Proportioning valve, Wildwood 260-8419 Summit or Jegs
    Kit to gut the stock proportioning valve Ford Racing M-2450-A Summit or Jegs
    Reuse stock brake booster – no changes needed with the parts in this list
    73 mm front calipers from a 91 Lincoln Mark 7 (two calipers) local auto parts store
    Emergency brake cable parts: Summit or Jegs or Late Model Restoration
    79-92 Mustangs use: M-2809-A* Parking Brake Cable (need 2)
    93 Mustangs: use 93 Cobra Ebrake cables.
    All years use: M-2810-A* Parking Brake Cable (short cable that attaches to the parking brake handle)

    I recommend that you use reman calipers and use the calipers from the Turbo Coupe axle for cores to return. The parking brake mechanism and the caliper slides tend to lockup and freeze

    Identifying a Turbo Coupe rear axle:
    1.) Measure the rotors - a TC disk brake uses 10 5/16" vented rotors.
    2.) Measure the length of the quad shock mount arm and compare it to the mount on your existing stock axle. The TC quad shock mount arm is about 8" long if I remember correctly.
    3.) Measure the distance between the axle flanges and compare it to stock. The TC rear axle assembly is 3/4" wider per side, or 1 1/2" wider for both sides.
    Fixing the added axle length problem:
    If the extra width is a problem for your wheel and tire combination, North Racecars makes some rather expensive brackets ($160 +) which allow you to use the stock axles. See http://northracecars.com/Brakes.html
    #17
  18. jcgafford

    jcgafford Well-Known Member

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    The T bird swap is an idea. Unfortunately i live in an area where all these vehicles were scrapped about ten years ago when scrap prices went thru the roof. I am stuck with either buying new and having them installed or looking on craigslist for a part out. And I have given up on the little gears. Minimal 3.55, max 3.73. All depends on what i can find and what the price is.
    #18
  19. ratio411

    ratio411 Founding Member

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    I wouldn't bother with 3.27s.
    3.55 to 4.10, depending on your tranny and where you do most of your driving.
    If you do most of your driving between red lights and stop signs, a lower gear (higher number) will give you better mileage.
    #19
  20. jcgafford

    jcgafford Well-Known Member

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    AOD, I live southwest of Ann Arbor. Outskirts of town not a lot of stop signs or traffic lights unless you head into town. I am down to 3.55 or 3.73 based on recommendations here. I realize a lot of guys want more gear than i do so i am leaning 3.55, but lets see what turns up on craigslist before i say i am firm on one or the other.
    #20

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