Tranny 4-speed or 5-speed Hmmmmm!

Mike Bartlett · #1 (**permalink**) 10-08-2003, 10:02 PM

Hi All,
I placed an order for a Cobra and I am anxiously awaiting its arrival in Dec.. About the only thing I have left to decide is 4-speed or 5-speed tranny. I will be installing a 427 S/O cast blk, aluminum heads. I also ordered it with 3.54 gears.

I like the idea of originality and quicker shifting of the 4-speed. But I also like the idea of the overdrive with the 5-speed when cruising on the hwy. If I go 5-speed should it be Tremec-TKO or
Richmond??

I thought I would put this out there to see what all you current Cobra guy's think.

Thanks in advance!!

Gear_Head63 · #2 (**permalink**) 10-08-2003, 10:27 PM

Personally, I'd say go with the 4-speed. It's tried and true and I really don't think these new 5 and 6 speeds are as tough as the old three and 4 speeds. Give me a T-10 Borg or a M-21 Muncie over one of those any day. I do sympathize on the issue of the overdrive though, but with 3.54 gears you aren't really going to need it. Hope this helps!

Edley Rondinone · #3 (**permalink**) 10-08-2003, 10:32 PM

What are you going to use the car for? Serious drag racing? Serious track racing? Originality a concern above all others? Just cruising around town, with the occasional car show/cruise night thrown in? Any regularly scheduled long trips planned? Overall, IMHO, I think the overdrive gives you much more flexibility. I vote for the overdrive. FWIW

Gear_Head63 · #4 (**permalink**) 10-08-2003, 10:42 PM

You bring up a good point my friend but I have to wonder if whether or not it would be worth. TKO's don't hold up like rockcrushers or super T-10s do. Either way though, at least you're driving a clutch and not some funky ass automatic! Yuk, I spit at such things.

Mike Bartlett · #5 (**permalink**) 10-08-2003, 10:46 PM

Gear_Head63,
I agree with you on the 4-speed toughness! They have def. held up through the years! But, that OD is a big draw!

Edley,
That is a good question. Ya know I hope all of the above. I would like to do some racing. Def. crusing along with some of the clubs to Tahoe, Napa, the coast, etc. Hell I still can't believe that I have actually ordered one.

Thanks for your comments.

decooney · #6 (**permalink**) 10-08-2003, 11:41 PM

I have a beefy 4-speed Toploader in my car. Its great, however, there are several times when I'm running on the freeway getting to places next to my other friends with the newer TKO 5speed...

Their engines are mildly crusing along, not spinning too many RPMs, easily going 75/80 at lower RPM, and my motor is over here spinning away even with 3.31 gears and taller tires. For around town and stoplights, the TL is nice. If you drive on the freeway for 1-3+ hours straight any time on periodic trips, it'll make you think some more about it.

... if you are not going to drag race the car, and you don't need to dump the clutch like a dingbat, the newer TKOs do nicely and you get to save your motor a bit in the process... I like the originality of the Nascar Toploader but none of these replicas are original Cobras, so who cares - it really comes down to what you like and need and how you plan to use the car. I may just yank my Toploader, keep it in storage for safe keeping, and go put a TKO 5speed in mine too. Good Luck.

Hal Copple · #7 (**permalink**) 10-09-2003, 04:53 AM

my SPF came with a 3550 Tremec five speed, with a reproduction forward bent shifter handle, so it certainly looks authentic in the cockpit, and is a big reason i have not switched my shifter handle out to one of the aftermarket ones. i do have a TKO shifter ball on it, it is a pretty short throw to shift.

As for the OD thing, i have many thousands of miles on my car, and love my fifth, just loafing along at about 1900 rpm in fifth at 60 mph, but with the 3.73 rear, real acceleration is just a flick of the wrist away. As for durability, running over 500 #'s of torque, and having about about 70+ drag strip runs, and about 800+ road course laps, it is strong as an ox. I did wear out two synchros with speed shifting on the drag strip, they were an inexpensive fix.

But the Tremec's are a robust transmission, and I like my up to 23 mpg at cruise, and the less wear on the motor.

CJ428CJ · #8 (**permalink**) 10-09-2003, 07:36 AM

Mike,

If you plan on using 3.54 gears, don't go with the Richmond. Richmond has a really low first gear and 5th gear is 1:1. If you want the Richmond, you'll want to go with a rearend in the range of 2.88 to 3.08. I'm running a Richmond with 2.88 gears and it's perfect. First gear is plently low and at 70mph in 5th gear I'm turning about 2700 rpms.

Chris

Chaplin · #9 (**permalink**) 10-09-2003, 07:52 AM

I am running a TKO II (.82 fifth) with 3.31 rear. Cruising at 70 the motor is turning about 2200, which is great. Cuts down on the noise, saves wear and tear on the motor and increases gas mileage. I would think the TKO II would be great with 3.54s, the only problem is that 1st gear (3.27) might be a little short with 3.54s. But some have said (Turk, I believe) that 3.54s and TKO II are the perfect combination.

DonC · #10 (**permalink**) 10-09-2003, 09:58 AM

Chaplin:
What are you using for wheels and tires? I'll be getting the same transmission and final drive ration in my ERA and I'm curious.
DonC

Chaplin · #11 (**permalink**) 10-09-2003, 10:19 AM

Don-
I've got the standard trigo wheels with 295/50/15 rear tires and 235/60/15 front tires. My only comment is to think about the cam shaft you are using when deciding on the rear gear ratio. I think the cam in my motor (Comp Cams 292H) might be one step too big for the 3.31s and probably would do better with 3.54s because it really likes to run above 2200 rpm. With that being said, I am going to run it for a while, dial in the carb a little bit and see how it goes. I might swap out the cam next year to something smaller, in which case I think the gearing would be perfect with the 3.31. But 5th really is a nice cruising gear.
Mike

RallySnake · #12 (**permalink**) 10-09-2003, 10:35 AM

Mike,

I'm running the same 3.31 ratio as you with the Tremec. With my big cam, I couldn't pull 5th at low rpm until I installed Rhodes lifters. These made a world of difference! I can go full throttle (with vacuum secondarys) at 1800 rpm in 5th and just pull away from anything. Well, except a Lotus 7 replica. One night coming home from a rally. We're cruising about 75 and he hits it. In fifth, I just stayed with him. After we slowed down, he was incouraged to try it again, I guess. In fourth, it was bye bye Lotus!

Steady cruising at about 70 will get 23 mpg with this set up. Not bad!

Paul

decooney · #13 (**permalink**) 10-09-2003, 11:00 AM

Hey Chaplin,
I know we talked about cam specs and gear ratio combos in the past a bit. I've been doing even more experimintation with tuning and believe I have come up with a way to make the car just a little more driveable at lower rpms, with the bigger cams and crusing speeds.

Send me an email on the following so we can compare.

- Your Carb type(s) and #
- Carb stock or altered some?
- Air Filter type(s)
- Jets in Primary & Secondary if you know
- Discharge Nozzle numbers used on carb
- Size of Power valves in carb
- Thermostat temp used
- Timing setting

Talk to you later.

James Baldwin · #14 (**permalink**) 10-09-2003, 11:09 AM

Are the rear transmission mounts in the same place on both the Tremec and TopLoader or do you need to modify the rear mount to accept the 5 speed? I have never had to switch one.

Chaplin · #15 (**permalink**) 10-09-2003, 11:19 AM

Duane-
I'll check the info tonight and shoot you an email.
Thanks

James-
I got a special adapter plate from ERA that allows you use what I believe is the stock top loader trans mount with the Tremec.

Paul- 23 mpg is a dream. I haven't figured mine out yet, but I can tell you, it's not close to that

Hal Copple · #16 (**permalink**) 10-09-2003, 01:02 PM

Mike Stenhouse, the owner/operator of the SPF Second Strike literature and web site, is quite a gearing guy. If you want to plug in some of your choices, you can use his gearing calculator on his Second Strike site,

try:

http://www.secondstrike.com/Technical/GearCalc.asp

But there is some truth to the above comments about displacement and camming, i think if i were to have to start from scratch, i would want about 2K rpm at about 60 mph (ha, which i have now), then select a cam that will give reasonable drivability at about that rpm as the lowest reasonable rpm, and try it.

A bigger, more torquier motor can do with a "longer" gearing.

But you can play a lot with Mike's calculator. It already has the different transmissions in it.

Personally, i would give away first gear, in order to run a reasonable cruise rpm. So running a TKO II, with the .80 fifth would be nice, to me, with a 3.23 rear. brings the cruise back down, and streatches out the "splits" in the shifting.

Mike's SPF has the 3.08, TKO II, with about 530 hp or so, very long legged gears, but needs just a titch of clutch slip from a dead start.

CJ428CJ · #17 (**permalink**) 10-09-2003, 01:31 PM

23 mpg? Wow, that's great. I get about 10 but when you're driving a car this fun, who the heck cares?

Chris

flipper35 · #18 (**permalink**) 10-09-2003, 01:40 PM

FWIW, as far as handling power I can give you as little background.

I use the a833 mopar 4 speed. When Chrysler designed this they basically took a BW T-10 and made it 30% larger. It is used behind all kinds of big torque blocks. The TKO-II has a larger input shaft, the gears are cut straighter and the gears are a bit wider across the face (although the a833 and TKO-II sync collars seem to be interchangeable). The engineering rep was quoted in Mopar Magazine as saying they run them all day in cars near 800 ft/lbs of torque. I wouldn't worry about breaking one. Actually, if I had 3 grand laying around I would get one.

Cracker · #19 (**permalink**) 10-09-2003, 01:44 PM

I might be a little off here but if I could start from scratch I would probably choose the TKO II from what I've experienced. I currently use a Richmond Gear 5 sp. which is supposed to be tougher and more user friendly for performance applications than a TL but less subtle than a TKO tranny. Externally shifted trans, from what I have seen do not shift as cleanly nor as quickly as internal shifters. With a TL or RG you will deal with this separate shifter issue - all you have to do is read the various threads pertaining to the problems/challenges/intricacies of these units.
The engine you see easily, the tranny you don't - my vote would be TKO II. Best wishes and enjoy your legalized replica - there's nothing quite like it!

Sizzler · #20 (**permalink**) 10-09-2003, 04:48 PM

This has been posted about before; I found it interesting.
You can have your cake and eat it too by installing a toploader initially, getting everything dialed in, then as funds allow, and if you STILL want the overdrive, you can just bolt on this unit to the end of the toploader. Most people think of add-on overdrives as being for automatics only, not so apparently:

http://www.gearvendors.com/racing.html>

GEAR VENDORS makes a kit to fit the Ford Top Loader and Jerico transmissions. The .78 to 1 ratio gives 28% more top end to the vehicle numerically and can be used in a variety of ways for the racer. Since the GEAR VENDORS can be shifted without clutching, it is decidedly faster when compared to a conventional shift. Imagine coming out of a corner or racing down a dragstrip where a foot or two could be very valuable and you have the option to hit a .78 multiplier under full throttle.

Some drag racers have found that using the overdrive version (popular in road racing) of the Top Loader with the ability to clutchless gearsplit the wide ratios makes for a great 5 or 6-speed.