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5 Speed Conversion

Discussion in '1965-1970 Shelby Mustang GT350 & GT500' started by BillH, Oct 12, 2006.

  1. BillH

    BillH Well-Known Member

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    Anyone done this to a 65 or 66 Shelby lately? I am giving it serious thought.
    I went through my Aluminum T-10 a few years ago when parts were still available and cheap. It works flawlessly, but I know that they don't last forever.
    My car has a Cobra scattershield and I would like to keep it and use the stock clutch linkage. I plan on using the Trimec with the .82 5th gear. There are a LOT of sources for these transmissions, some more reasonable than others.
    Anybody done this?
     
  2. The Commissioner

    The Commissioner Well-Known Member

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    We use the World Class T-5 on our GT350 resto's, and use the Mustangs Unlimited mounting kit which is about $400. Comes with crossmember and other assorted parts, but they're backordered on the kits last time I checked. It really is an easy swap, some minor modifications are needed to ensure a good fit, but it's very basic of a job. The T-5 is .63 OD. We use the TKO 600 for the Superformance Cobras and Daytonas with the .85 OD. The last Mustang we did had a 347 Stroker 400hp and the T-5 gearing was great with a 3:50 rear w/traction lok. When I finally get around to it, I plan on doing the 5spd conversion in my own 67 GT350 Shelby, that OD great is a must for cruising these days. I have my own source for the Tremecs, which are great products, no matter which one you use. The clutch linkage remains the same, but there is an adapter plate that has to be used which comes in that install kit.
     
  3. JamesFee

    JamesFee Well-Known Member

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    Bill,

    I put a new T5Z in my 66 about 4 months ago and have to say that it was the single best upgrade I have found for making the car fun for weekend drives again. I have a 3.89 rear (was 4.11) and the engine was screaming whenever I had to run down a highway (4-5k RPM). I may drop the rear ratio to 3.5 due to the close ratio of the trans gears.

    I went with Modern Driveline -
    http://www.moderndriveline.com/about.htm

    I found it particularly helpful to have someone to go through the whole project with (I was also installing a 347 stroker). Bruce Couture is the owner and very knowledgeable. I also like his crossmember better than the California Pony Cars unit. I was keeping my Cobra scattershied and old Z-bar, so it was more of a mix and match situation than going with a completely new setup with cable clutch etc.

    There's a good article on this (and several related topics) at Ford Muscle:
    http://www.fordmuscle.com/archives/2000/09/t5swap/

    I wish you luck in your research.

    j

    Jim Langendoen
    6s1801
    6s2021
     
  4. eljimb0

    eljimb0 Well-Known Member

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    I did it to my clone. I would have to echo the statement that it is the single best thing you can do to these cars to improve them... I used a T 5 and it is great. I have a steel bell housing and the adapter plate. Standard clutch linkage... The old speedo cable (from a T10) just went right into the hole in the new tranny.. The conversion was that nice. I have the regular 4 speed shifter attached to the T5.. You have to get under the car and look to see that it has been done.

    Highly recommended!!!!
    jimbo
     
  5. jimk351c

    jimk351c Active Member

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    The TKO / 3550 could require modifying the tranny tunnel in an early car. A t5 / t5-z will bolt in without having to modify any metal. I installed a T5-Z into my '70 Cougar with a JMC hydraulic clutch setup. With a hurst t-handle shifter, it looks very period correct.
     
  6. BillH

    BillH Well-Known Member

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    I had planned on using the TKO 600 trans. That one has a .82 fifth gear which means with 3.89's, final drive ratio is 3.19.

    With the TKO-500 5th gear is .68. Final dirve with 3.89's would be 2.65.

    My car has 24.5" tall tires, and 3.89's. SO:

    Stock 4 speed
    60 MPH = 3200 RPM

    Using the TKO 600:
    60 MPH = 2625
    Using the TKO 500:
    60 MPH = 2181

    The camshaft in my car would not work with the TKO500.
     
  7. jimk351c

    jimk351c Active Member

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  8. BillH

    BillH Well-Known Member

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    Thanks, Everyone. The final word is the Tremec TKO500 and 600 transmissions will not fit without modifying the floor. That eliminates these transmissions from consideration. I have pretty much decided on a T5z with a .8 overdrive. This makes an effective final drive ratio of 3.11:1, just about ideal for what I want to do.
     
  9. eljimb0

    eljimb0 Well-Known Member

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    Bill,
    I have the C7---"lemans" cam on my 289.. It is kind of old school bumpy.
    (great sound with an X pipe!)..55 mph = 2000 rpm. It is perfect on the hi-way. If you want to get away from some rice rocket drop her down to 4...
    .... But With 3.89 gears I wish my T5 had the first gear modification that made first gear faster.. It has this granny gear thing going on that is not quite right.... It is OK, but if I ever take the tranny out again it is going to be fixed...
    Think about it,
    jimbo
     
  10. BillH

    BillH Well-Known Member

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    Jim
    By granny gear, do you mean the 3.27 low? Yea, I don't plan on pulling many stumps with my Shelby. I would love to find a 5 speed with a low gear in the 2.5 range, a 1.6 2nd, and a 1.2 third with a .8 fifth. That's not going to happen. That third gear in the T-10M is great on the twisties. They really did there homework.

    I was really disappointed with the ratios in the 6 speed. A .82 fifth and a .63 sixth? How many overdrives are needed? Seems to me that they could have spaced out the ratios better and had sixth gear as the overdrive.

    I really have a hard time understanding the wisdom behind a .63 fifth gear. Most of the 9" Ford rear ends I have pulled from passanger cars had ratios in the 3 to 3.25:1 range. If you had a performance car, Shelby or other wise (Ford, of course) you would have to have a set of 5.13's to equal this. (5.13 X .63 = 3.23). Anyway, it looks like I am going to get a T5z for my car with the 2.95 low and a .8something fifth.
    Later
    Bill
     
  11. eljimb0

    eljimb0 Well-Known Member

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    Bill,
    Somebody out there has a cluster gear kit.. with all the parts to do it.... it changes the lower gears to more workable ratios..If you are looking for a good used T5 you wll probably need to go through it anyhow.. It is a nice tranny to work on.. I got the manual and had mine all apart. It was much easier to do than the parking brake, tail shaft, exhaust X pipe, confluence...
    (the one square foot of hell under my car).
    good luck with the swap ...you will love what it does to your car.
    jimbo
    also.. this is important.
    There is a sleeve on the output shaft of the tranny that drives the nylon speedo gear. It has two ratios (I think one is seven turns and one is eight...)
    One of them is impossible to get the corosponding nylon gear for so your speedometer is correct.. It is easy to change the sleeve when the tranny is on a bench.. durn near impossible when it is in the car.. Do the homework on this and save yourself some frustration...
     
  12. skidado

    skidado Well-Known Member

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    Just for fun (I'm bored at work today :sleepy: ) I thought I would do a spreadsheet of the thrust curves for the toploader and the T5Z.

    I have the gear ratios for the T5Z and the toploader (is it wide- or close-ratio for a '67 GT350?), but I can't find a reliable torque or power curve for the shelby-ized Hipo 289.

    If anyone could point me to one that would be a big help.

    Once done, I will try to share the spreadsheet (or at least a picture of the thrust curves) on this forum.

    Thanks for any help you can give
     
  13. jimk351c

    jimk351c Active Member

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    Good point. Let me add to this, be sure to use a speedo gear clip for a T5. A toploader / C4 speedo gear clip will not keep the T5 speedo gear in place. This can result in the speedo gear coming loose (ask me how I know!). In my case, the speedo gear actually wedged against the drive gear and pushed it off the clip that holds it in place. This forced me to pull the tranny out and remove the tail shaft.

    Good luck.
     
  14. 67GT500#2100

    67GT500#2100 Shelby Forums Pit Crew

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    I put a T-5 in my 66 fastback with a 3.89 gear, If you are going to change the internal speedo gear put in a black 6 tooth from a 87 turbo coupe t-bird. This makes speedo correction even easier as you can use production cable gears form Fox body Mustangs. I bought my 6 tooth gear right from a Ford dealer just a few years ago, it was cheap then I also used a yellow 17 tooth gear on the cable. My speedo is right on accurate with my 17 inch tires.
     
  15. cushman350

    cushman350 Member

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    Did the same to my 66 with also a 389 rear. My speedo is now 10 mph too fast with a 21 tooth driven gear and 225/60-14 rubber. Don't know what drive gear is on the tail shaft( 6,7, or 8) now but I think I need less teeth than I have now to slow the driven gear down, right?
     
  16. BillH

    BillH Well-Known Member

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    The speedo in my car has never been right. At a true 56 MPH, the tach reads 3000 RPM. The speedo reads 72. I have the reduction box that goes between the cable and the speedo, just never got around to installing it.
     
  17. jimk351c

    jimk351c Active Member

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  18. Jerry_Moss

    Jerry_Moss Well-Known Member

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    Hi guys

    One questions to the Commissioner
    What do you mean by:
    some minor modifications are needed to ensure a good fit
    And to the guys who drive the T5 with .63 O.D.
    If you accelerate in 5th gear is it powerful or more or less dissapointing?
    Please also tell me your rear end ratio.

    Thanks Jerry
    :thumbsup:
     
  19. crzy4shelbys

    crzy4shelbys Well-Known Member

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    Hi Jerry,

    I did a T-5 conversion about a year ago. The T-5 will fit the trans tunnel without mods. In my case I had to shorten the driveshaft, but I've heard that a lot of people don't need to. I've heard some people need to slightly modify the hole in the tunnel for the shifter to clear. I did not.

    The TKO requires mods to the trans tunnel in a '65-'66 to acheive the correct drive train angle. There are cross members out there that will allow you to install a TKO without modification to the tunnel, but the result is a drivetrain angle that is outside the aceptable range.

    With the T-5 there are a number of choices to adress with the bell housing/clutch setup (289/302 bellhousing/clutch linkage with a spacer between the tranny and bellhousing or 5.0 bellhousing and clutch). I went the route of using a 5.0 bellhousing and clutch so I'd get to use the bigger 10.5" clutch, which meant I had to find a 28 ounce imbalance flywheel drilled for a 10.5" clutch (the modern 5.0's are 50 ounce imbalance, the 289/302's used a 10" clutch) because the clutch release fork pivots on the opposite side of the bellhousing on a 5.0, I had to figure out how to make a clutch cable work. I didn't like the kits available, and wasn't happy with what I came up with, so I ended up using a hydraulic kit, which mounts a slave cylinder on the side of the trans to push the release fork from the tranny side (same as a cable pulling it). In the end, I was very happy with the hydraulic setup.

    I run 3.89 gears in a 9". The acceleration is not great in 5th gear, but your engine will probably have a lot more punch than mine. Either way, I use 5th gear for highway cruising only.

    You're not considering this for your R-model replica, are you?

    Josh
     
  20. Jerry_Moss

    Jerry_Moss Well-Known Member

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    Hi Josh

    Thanks for the reply.
    One question is still there.
    Why do some have to modify the hole for the shifter and some not???
    Every car and tranny s the same have you a answer to this?
    And yes i want it for the replica. I know i know not original but you know
    that germany is one big race track! ha ha ha And i need to go more that 160
    with this car on open road without distroing my 12,5:1 engine at high rpm.

    Hope you agree with me. :guitar:
    About the clutch i have to get back to you because on this subject
    i´m still a greenhorn without any experience. And when i read balancing
    flywheel and oz i just understand nothing anymore.
    My engine is a 302 out of the 70tees.

    What about alloy flywheels? Expensive but good??

    Hope you can help
    Bye Jerry


    P.S. Here is how i modifyed my clutch pedal bracket
    http://saacforum.com/index.php?topic=1762.0
     

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