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Thread: What type of transmission did you choose and why?

  1. #1
    Join Date
    Mar 2009
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    san angelo, texas
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    12

    What type of transmission did you choose and why?

    I was wondering if you guys would tell me whether you chose a 4,5, or 6 speed transmission? What were the positives of your choice and if there was anything you would change now, what would it be? Also if you would mention your hp and rear-end gearing, and how you use your car, as well. I am trying to make this difficult decision right now. Please help!

  2. #2
    Join Date
    Jan 2009
    Location
    Moorpark, CA
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    160
    I haven't built mine yet but plan on a 5-speed. I considered a 4-speed to be period correct, but I plan to do a lot of freeway driving and the OD 5th gear puts less wear and tear on the engine.
    Bill D

    Slowly accumulating parts to build a period correct 289FIA


  3. #3
    Join Date
    May 2004
    Location
    Clinton, TN, USA.
    Posts
    1,287
    step back and consider the type of driving you will be doing, the rear end ratio you want and then the power range of the cam you will have in the engine. With a 2400 pound car you don't need a lot of muscle to make it into a rocket. Most of my drives are in the 50-70 mile and hour range, I've got a 3:31 with a 4 speed. My rpms are about 2000-2100 for 60 mph and my cam does not fit the driving profile as it comes in around 2500, hence another change next winter to a different cam.

    for what is worth...

    Ralph

  4. #4
    Join Date
    Jul 2003
    Location
    Kansas City, MO, USA.
    Posts
    256
    For me, the top-loader isn’t an option, as I’ve driven too many Cobras with them and those drives made me realize that I want an overdrive gear (even if it’s just a .82). The majority of fellas in the Mid-America Cobra Club who have top-loaders in their cars are always belly-aching about the same thing. They say that the top-loader is fine when just cruising around town and in between stoplights, but they stink on the highway (especially with a 3.50 or shorter rear gear).

    Plus, I felt that the shifting mechanics of the Tremec is much better than the top-loaders I’ve driven. The Tremec just has a much more solid, positive shift-feel to it. Besides, when you put the right shifter and 4-spd shift knob on top, nobody knows what transmission you are running unless they crawl under.

    The only thing I may change now is upgrading my Tremec 3550 for a TKO 600 with the road race 5th gear ratio. My final gear is a 3.31, so at the road courses I run, I think the .64 5th gear may come in handy.
    Unique 289FIA - Chassis #9229 - Viking Blue

  5. #5
    Join Date
    Nov 2003
    Location
    Cincy, OH, USA.
    Posts
    376
    My setup is a 428 and a top loader with a 3:54 gear, runs about 3100 rpm at 65mph. The cam you choose should be considered carefully because anything less than 2000 rpm on my setup is not good for crusing.
    Scott
    4279454
    SA 428
    3:54

  6. #6
    Join Date
    Jan 2003
    Location
    Shepherdsville, KY, USA.
    Posts
    1,725

    Smile Top-Loader

    I am a fan of the period correct toploader, close ratio, mine is a 427, approximately 510 HP, 3:73 rear gear. I drive mostly back roads in the Blue Grass State. Some stop and go driving, red-lights, I love Mustangs!!!
    and Camero's.
    Rick
    427 S/C , 427 Side-oiler, 4 Speed Close Ratio Top Loader, 3:73 Gear
    #4279405

  7. #7
    Join Date
    Jan 2004
    Location
    Houston, Texas
    Posts
    137
    I used a 5-speed Tremec TKO 600 with a .080 5th gear and mid-shift kit with a 3:42 limited slip rear end in my FIA. I haven't had it on the highway yet so don't know what the RPM's are in 5th gear at freeway speeds.
    Terry
    Viking Blue 289 Competition Model
    #9527
    Southern Automotive 351W
    Tremec TKO 600 5 speed
    3:42 Limited Slip
    3-piece Compomotive 17" Pin Drives

  8. #8
    Join Date
    Jan 2003
    Location
    St. Augustine, FL
    Posts
    398

    Talking Choices, choices......

    You got a few to make. All the advise above is spot-on, because the engine and its characteristics factor so heavily into gearing setups.

    Ever partial to small blocks, I went with a 4.09 rear and the Tremec 3550 5 speed with a 0.64 5th gear. Screaming power in all gears, with deep enough reserve in 5th to cruise the interstates - 75 mph is 2500 rpm, right where power starts building fast. 60 mph in 4th is 3000 rpm, and makes for easy street manners. With a 7000 rpm redline, every gear in the box is just right .
    Yeehah

  9. #9
    Join Date
    Jan 2003
    Location
    Harrisburg, PA, USA.
    Posts
    657

    Toploader

    I'm all-in with Eliminator on this one. Period correct adds inherent value to your vehicle. Also the Toploaders were so over engineered in support for Ford's Total Performance program that they are virtually indestructable.

    With the twin Paxtons my engine is solid in the 7's and maybe as high as 800 hp. The rear is 3.31 which has the pipes sounding a deep 2700 RPM cruising Purr at 65 MPH.

    - Geary

  10. #10
    Join Date
    May 2005
    Location
    Roseville, Ca., USA.
    Posts
    523
    drbb, you should check out the link in this other thread http://www.uniquecobra.com/forums/showthread.php?t=7917
    the site lets you imput all of your data and gives you RPM and MPH in all gears, might help you with your decision.
    Rod
    Roseville, Ca.
    289 FIA #9152 "The Flintstone Cobra"

  11. #11
    Join Date
    Mar 2009
    Location
    san angelo, texas
    Posts
    12
    Thanks everyone for the comments. Anyone running an engine in the 600+ lbs torque range? I am hoping to have a car I can drive daily but also to take frequent trips to visit family in nearby areas (70-110 miles) and I'd like to be comfortable driving those distances. What problems can you foresee trying to match these things but keeping as much of that "tire-squealing, screaming rocket from light to light" fun that I also need? I realize there will be compromise somewhere. Hope this makes sense?

  12. #12
    Join Date
    Jan 2003
    Location
    Harrisburg, PA, USA.
    Posts
    657
    Get Bill Parham to build a Super FE for your project.

    www.southernautomotiveengines.com

    Gut wrenching power and reasonable price.

    As far as 100 mile trips it's easy in a car like this. A few Unique owners (including myself once) have driven their cars thousands of miles roundtrip to attend Cobrafest. The major problem is not the engine but the foam in the seats. Many Unique customers add a bit of higher density foam for extended travel. Search this site for seat foam modifications.

    Bottom line is that you want a vehicle that you can use. You can get away with a more radical engine on the street if it's only dragging a 2500 pound vehicle. The only qualifier is that at the end of the day it has to be streetable. For consideration a bone-stock 428 will throw you back hard in the seat, light the tires at will, and makes a great cruiser. 600+ ft/lbs of torque is great bragging rights but once your tires have lost traction you don't travel any faster.

    You’re only limited by the depth of your pockets. Talk to Bill or another good machinist and describe what you want to get for the dollars available. That’s what I did in 2000 and now have an extreme FE that will also idle at 950 RPM in 4th gear pulling smoothly at 18 MPH with foot off the throttle. I did this in a ½ mile loop through my neighborhood last week.


    -Geary

  13. #13
    Join Date
    Mar 2009
    Location
    san angelo, texas
    Posts
    12

    Smile

    Thanks aggressor. I already have the engine it is a Ponds 427 SO (stroked to 487) that Keith Craft built with 625 HP and 620lbs torque. It is waiting for my decisions about transmission and rear-end gear. In fact Alan and Maurice are waiting as well. I hope to make a decision very soon. The information given so far has been very helpful. I guess I just wanted to hear what others have learned before I commit one way or the other to a 4, 5 or 6 speed. Trying to do it right the first time.

  14. #14
    Join Date
    Jan 2003
    Location
    Harrisburg, PA, USA.
    Posts
    657
    I did not realise that you had you engine selected. The 487 stroker sounds like a very fine choice. Just practice using light toe pressure on the load pedal. Keeps you safe. With my project I'm at the point where I can't really conceive of a situation on the road that I would even come close to opening the secondaries. High HP, fat tires, short wheelbase can make for a very dangerous situation. Never fear it ... Just give it appropriate respect.

    - Geary

  15. #15
    Join Date
    Dec 2004
    Location
    Prince Frederick, Maryland, USA.
    Posts
    1,561
    I have a 482 stroker with a close ratio toploader and a 3:31 posi lock.
    not a bad set up but I would recommend a TKO600 w/ .82 5th and a 3:24 Posi Lock.

    With that kind of power do not skip the posi lock rear and get the big brake upgrade.

    I feel the car is much more predictable with the posi lock.
    Tony
    Unique 427 #4279480 Precision Engine Machine Company 427 s/o 483.47 stroker close ratio toploader 3.31 jag rear

  16. #16
    Join Date
    Mar 2009
    Location
    san angelo, texas
    Posts
    12
    Naumoff you recommended posi trac. It sounds like you have tried with and without posi trac? What hp, torque range is your engine, if you don't mind me asking? Do you have the clunking I hear several people mentioning that can come with posi trac? Alan and Maurice were both discouraging as far as it was concerned, is there a down side? What is the downside to not having posi trac? More spinning? I am just trying to learn enough to make the right decisions the first time, thanks for your input.

  17. #17
    Join Date
    Mar 2009
    Location
    san angelo, texas
    Posts
    12
    I noticed I typed in 487 earlier instead of 482. My engine is stroked to a 482.

  18. #18
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    Mar 2009
    Location
    san angelo, texas
    Posts
    12
    Quote Originally Posted by ralphscott View Post
    step back and consider the type of driving you will be doing, the rear end ratio you want and then the power range of the cam you will have in the engine. With a 2400 pound car you don't need a lot of muscle to make it into a rocket. Most of my drives are in the 50-70 mile and hour range, I've got a 3:31 with a 4 speed. My rpms are about 2000-2100 for 60 mph and my cam does not fit the driving profile as it comes in around 2500, hence another change next winter to a different cam.

    for what is worth...

    Ralph


    What cam duration and lift are you using and what do you hope to switch to?

  19. #19
    Join Date
    Mar 2009
    Location
    san angelo, texas
    Posts
    12
    Quote Originally Posted by Aggressor View Post
    Get Bill Parham to build a Super FE for your project.

    www.southernautomotiveengines.com

    Gut wrenching power and reasonable price.

    As far as 100 mile trips it's easy in a car like this. A few Unique owners (including myself once) have driven their cars thousands of miles roundtrip to attend Cobrafest. The major problem is not the engine but the foam in the seats. Many Unique customers add a bit of higher density foam for extended travel. Search this site for seat foam modifications.

    Bottom line is that you want a vehicle that you can use. You can get away with a more radical engine on the street if it's only dragging a 2500 pound vehicle. The only qualifier is that at the end of the day it has to be streetable. For consideration a bone-stock 428 will throw you back hard in the seat, light the tires at will, and makes a great cruiser. 600+ ft/lbs of torque is great bragging rights but once your tires have lost traction you don't travel any faster.

    You’re only limited by the depth of your pockets. Talk to Bill or another good machinist and describe what you want to get for the dollars available. That’s what I did in 2000 and now have an extreme FE that will also idle at 950 RPM in 4th gear pulling smoothly at 18 MPH with foot off the throttle. I did this in a ½ mile loop through my neighborhood last week.


    -Geary

    Just wondering what kind of cam you have? You mentioned you can cruise at 65 in 4th at 2000 rpm, and idle in 4th at 950 rpm. It seems your cam would be very important in your setup. Do you not have problems with bogging down at 950 rpm in an engine that will do 700 to 800 hp? I am just learning so if I ask my questions poorly please forgive me.

  20. #20
    Join Date
    Mar 2009
    Location
    san angelo, texas
    Posts
    12
    Quote Originally Posted by RJacobsen View Post
    drbb, you should check out the link in this other thread http://www.uniquecobra.com/forums/showthread.php?t=7917
    the site lets you imput all of your data and gives you RPM and MPH in all gears, might help you with your decision.

    Excellent website, I have used it extensively since you posted it. Thanks.

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