Can a WC T5 handle a 331 stroker?

Discussion in '1965 - 1973 Classic Mustangs -General/Talk-' started by synthartist69, Jan 31, 2010.


  1. synthartist69

    synthartist69 New Member

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    I have been considering swapping my 4 speed for a T5. Currently I have a hipo 289 but at some point would like to swap it for a 331 stroker around 375hp. Can the T5 world class handle the torque of a 331 stroker? This is a street racer(65 fastback with 3:73 gears). Any input would be greatly appreciated!

    Jim
     
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  2. woodsnake

    woodsnake Active Member

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    My understanding of what kills a T5 is the hard launches, not "spirited" driving.
     
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  3. blkfrd

    blkfrd Member

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    If you have a T5 with the strengthening mods that were incorporated into the T5z, yes it will be fine with street tires. I have road raced my car and beat the T5z trans very hard and have had no ill effects. The trans is behind a 331 with approximately 425 HP. Modern Driveline claims that the dual kevlar clutch tends to reduce shock to the trans. I have this clutch and a hydraulic clutch pedal and it's a wonderfully smooth and low pedal effort system. MD uses this same setup behind a 500 HP small block used for road racing
     
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  4. synthartist69

    synthartist69 New Member

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    What year mustangs have the t5z? thanks!

    Jim
     
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  5. Decurion

    Decurion Member

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    93 Mustang Cobra. Just buy a new one from Ford Racing, or get a used one on ebay or craigslist or something. Just be careful what you get, t5's have somewhat of a reputation for getting beat up. I got hosed pretty bad on one, so I speak from experience.
     
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  6. synthartist69

    synthartist69 New Member

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    I know what you mean. I see a lot of t5 transmissions on Ebay, some look very suspicious and too good to be true.
     
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  7. Sicarius428

    Sicarius428 Active Member

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    I would say if you are going to drive the 331 like its intended... no. Ask me how I know and I only have a 302 with H/I/C... The t5z is rated for 330ft lbs. If you drive it like a granny then it should be fine but launches and hard shifts spell dealth for any t5. If you get a gforce one you should be just fine but at that rate you might as well get a tko...
    Kevin
     
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  8. blkfrd

    blkfrd Member

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    Sicarius is correct about the 330 ft/lb comment, but this spec is based on the life of the trans and not a one time incident. Shock is what kills the T5s and any other trans for that matter. If you put sticky drag tires on the car and rev the tach to 5000 and dump the clutch, your T5z or WC T5 will surely complain sooner or later. Street tires...no problemo. My trans would have broken if a one time shot over 330 ft-lbs does in a T5z and Modern Driveline's 500 HP road race car would have not made it around one lap
     
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  9. v8only

    v8only Active Member

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    the cobra's actually just got the standard 3.35 wc t5 that all the other mustangs got. The difference is that the cobra's got the tapered bearing on the front, where the other mustangs did not. This tapered bearing is shared with the z specs.

    A new z spec costs $1300 + ship.

    You can build your own z spec for $400 or less, give or take for the hard parts which includes 1,2,3,4 gear, new cluster, new input...+ $150 for new syncro's, bearings and small parts and you've got a z at half the cost.

    the z spec was a ford racing only trans. The easiest way to tell if you have a z is the 2.95 first gear ratio...rotate the input, count the output turns..all other w/c trannies received a 3.35 first gear ratio. Also, don't confuse a z spec for an 83/84 non world class t5. I see people get screwed this way. the 83/84 non world class t5's got 2.95 first gear ratio but are NOT world class spec! You can always tell a nwc t5 by the bolt on the top middle pass side of the case. If it's a hex bolt, it's a nwc t5. If it's a torx bit, it's a wc t5

    a z spec will handle up to 450 horse, but as mentioned if you're on slicks every weekend, look to move to a gforce or tremec....for a mostly street machine though, you'll be just fine. The thing that kills t5's is powershifting, period. My friend launched a 321 at the wheels coupe for 2 seasons on slicks with a z spec and didn't break it. I built a t5 for a friend and within a month he shattered it by powershifting at the track with nitrous. don't powershift!
     
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  10. synthartist69

    synthartist69 New Member

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    Thank you for all the info! One thing I have noticed about the t5z is that it has a higher 5th gear at .63 as opposed to .68 on a regular t5. I like the higher gear for sure!
     
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  11. synthartist69

    synthartist69 New Member

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    Thank you for the comment! I will not be running slicks or speed shifting. I will be jumping on it from time to time, and definitely want to have it there if I need it! It looks like the T5z is the way to go, now it just comes down to finding one that is in good condition or rebuilt at the right price. What would be a good price for a rebuilt T5z. I seen that a seller on Ebay has them for about 900.00 plus a 250.00 core charge.
     
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  12. 65ShelbyClone

    65ShelbyClone Founding Member

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    Front....as in input shaft?
     
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  13. v8only

    v8only Active Member

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    actually the very tip of the mainshaft that the end of the input shaft slides onto.

    standard w/c trannies had insert type individual bearings that you manually insert into the end of the input shaft. these indiv bearings then fit over the end of the mainshaft tip, and that's what allows the input to spin independently of the output shaft(Main shaft). the cobra trannies and z spec did away with the insert style bearings and went to a pocket style bearing, or in other words a wheel bearing style bearing with cage that presses onto the end of the mainshaft. this one piece bearing goes into the end of the input shaft...and the input shaft is different therefore is different for the cobra's and z specs.

    the benefits are an additonal 10-15 pounds torque capability and the ability to put more preload on the input during assembly.

    however, because the mainshaft is different on the cobra than the normal w/c trannies, while doing a z upgrade on a normal t5, the bearings at the input/main tip cannot be upgraded. Not the biggest of deals though, as the significant upgrades come through the upgraded gears.

    you can get the super alloy "z" upgrade kit on ebay for $379 right now from the gear box. This includes a brand new 1,2,3 gear and a brand new input shaft with 4th gear and a new cluster shaft. get the $150 rebuild kit including bearings, syncro's and small parts, and upgrade your existing t5 to z spec for about $600 out the door. this is $700 cheaper than a brand new z spec, and when you're done, almost everything is new. (get the hanlon how to video, that's how I learned!!)

    I've built several of these now for people, and with my labor I charge $800 out the door for a z spec upgraded t5...lol that's the price most others are paying for a "stock" rebuild at a normal shop.
     
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  14. BlownFiveLiter

    BlownFiveLiter have car, will race....wait, it doesn't run

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    I would disagree about a Z-spec trans holding 450 HP. I broke one with a stock engine in my 95. Granted I'm typically hard on cars anyway, but I would have expected it to survive more. Look into the G-Force transmissions, if you're looking for a T5 that will really live behind a 331. If I'm not mistaken, the G-Force gearset tends to run right around the same price range as the whole T5Z does, so you'll have a little more expense with putting one together, but you'd be able to rest assured that you're not going to grenade the thing.
     
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  15. v8only

    v8only Active Member

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    I would tend to agree, but there are certain ways that a t5 has to be treated to live a long life.

    if you go to astroperformance.com...they sell the t5z and the upgrade to convert yours, and they refer to it as the 450 horse kit.

    there are several other sites too that claim 450 horse. I would never run one with that much power though, unless it was strictly a street machine on street tires only
     
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  16. 10secgoal

    10secgoal Active Member

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    Huh, anyone else thinks the mods just might be getting bored in here ? Seemed like tech to me.
     
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