Thread: TH400 VS. T56 6 SPEED? Faster? Better?

Tweet

Hello, I am new to the site. I am reading alot about Auto's Vs. Manuals. Obviously an automatic is a quicker more efficent shift, if you are comparing the equall amount of gears. However if you compare 3 gears in an automatic to a 5-6 speed manual, is an automatic really quicker? with the right gearing, isn't a 6 speed like having a 3 speed transmission with in between gears like a 2 1/2, 2 3/4 and an extra 3 1/2 gear? would this not keep you in you horsepower range more efficently? I know a TH400 has an equall 1st gear, however second is like a 1.7 to 1 wherein the 6 speed is like 2.2. In the same car wouldn't the 6 speed run a better 1/4 mile and have better top end?

The reason I am so interested is because I am considering putting a 6spd trans in my 67 camaro with a TH400 w/3500 stall. The cost is between $2500-3500. I would hate to spend all this money if it is not going to make a significant difference. Any feedback is appretiated

For basis of comparison with a T400, the T-56 is more like a 4 Speed because the 5 and 6 gears are actually overdrive. If the car is a street/strip car then the T-56 would allow you to run a much lower rear-end gear and still have a reasonable cruise RPM because of the overdrive. How do you plan to use the car?

Pat

It is a street car and it would be great to have overdrive. I will be cruising it around the streets. The most significant thing for me is will the 2-4 shift provide a lot faster acceleration then the automatic. The gear ratio drop from 1-2 on the TH400 is significant.

Hi MGONCHAR,
I know your 67 Camaro very well. I would install a TKO-500 or TKO-600 into your car in a heartbeat.
I developed and installed the first GM Tremec 3550 into my 1968 Z-28 back in 1993. With the overdrive I was able to reduce engine speed 32% from 3000 rpm to 2040 rpm. The TKO-600 has a 36% overdrive and reduces rpm from 3000 to 1920 rpm.
This is a bolt-in that can be done in less than 3 hours on your garage floor if you know how to work on cars. The only delay would be to shorten the driveshaft.
BTW, The T-56 requires much more modifications and really isn't worth the extra cost and labor in my opinion....
Call me with any questions or price quotes.
Mike Forte
mike@fortesparts.com

For bracket racing you'll want the auto... For street racing (ahem) I mean cruising you'll want the 6 speed... All things equal (ie rear gear) you will have slightly better accelaration and significantly better cruise rpm and mpg not to mention it's more fun to drive a stick... When it comes to consistency on the strip an auto is hard to beat... Or a Lenco or similar clutchless manual....

Hope this helps...

-Chris

Originally Posted by skids72

For bracket racing you'll want the auto... For street racing (ahem) I mean cruising you'll want the 6 speed... All things equal (ie rear gear) you will have slightly better accelaration and significantly better cruise rpm and mpg not to mention it's more fun to drive a stick... When it comes to consistency on the strip an auto is hard to beat... Or a Lenco or similar clutchless manual....

Hope this helps...

-Chris

I've raced brackets for years, with a 5 speed mostly, sometimes an automatic.... If your good with the manual, keep up with the clutch adjustment, it can be a very consistent car. I've ran both a clutchless five speed and a T-5, both were very consistent, it's a matter of doing the same thing every round...especially the burnout and staging....

On the street, it's not even a contest. with the five speed I can short shift, feather the throttle, or do whatever I need to do to keep the tires hooked and the car going straight.

I'll never say it's BETTER to run the 5 speed, just that it can be IF you run the right parts, keep things adjusted, and keep up with the track and the weather.... I've had many days that my old 5 speed car could stay plus or minus a few hundredths throughout the session. When you get into the quick rounds, like a Gambler's race, always enjoy smelling them overheated flowerglides come up to the line......

Anyway, don't ever let anybody tell you that you can't be competitive with a five speed in a bracket car.....You can be, if you work at it intelligently.

For Mike Forte----- Your opinion, good sir..... A TKO 600, with 5th geared at 1:1, a McCleod soft lok clutch.... can it be done and will it work? I'm an old Doug Nash guy, please help me advance out of the stone age!!!!

Originally Posted by Dave Severson

I've raced brackets for years, with a 5 speed mostly, sometimes an automatic.... If your good with the manual, keep up with the clutch adjustment, it can be a very consistent car. I've ran both a clutchless five speed and a T-5, both were very consistent, it's a matter of doing the same thing every round...especially the burnout and staging....

On the street, it's not even a contest. with the five speed I can short shift, feather the throttle, or do whatever I need to do to keep the tires hooked and the car going straight.

I'll never say it's BETTER to run the 5 speed, just that it can be IF you run the right parts, keep things adjusted, and keep up with the track and the weather.... I've had many days that my old 5 speed car could stay plus or minus a few hundredths throughout the session. When you get into the quick rounds, like a Gambler's race, always enjoy smelling them overheated flowerglides come up to the line......

Anyway, don't ever let anybody tell you that you can't be competitive with a five speed in a bracket car.....You can be, if you work at it intelligently.

Well Dave, you are just that good! I'm talking about mere mortals here yes there are many good 5sp racers but generally except for lenco liberty etc they are at a disadvantage... Out here we have a separate class for stickshift for this reason... Flowerglide true auto only as consistent as you can keep the temp...

What would be nice to clarify would be in a street race what would be better. For example, if you are going 40-50MPH the Th400 would be in 2nd gear with a much lower gear ration then the 6 speed in 2nd. Wouldn't the same car with the 6 speed excellerate a lot faster?

Originally Posted by skids72

Well Dave, you are just that good! I'm talking about mere mortals here yes there are many good 5sp racers but generally except for lenco liberty etc they are at a disadvantage... Out here we have a separate class for stickshift for this reason... Flowerglide true auto only as consistent as you can keep the temp...

I tell ya, the new 5 speed stuff is fantastic!!!! Just can't wait till I can justify a new G-Force clutchless 5 speed for the Ranchero!!!! Meanwhile, think I might have to hit up Mike Forte for a tweaked out TKO.

Heck, I'm not only mortal, I'm old!!!!! I started out with 4 speeds, bought the first Doug Nash 5 speed I could get my hands on, and never quit using them!!!!! It's not all that tough to be good with one, nothing that a couple decades of shiftin' them won't take care of!!!!! If the 5 speed car has a disadvantage, it's more then likely the driver!!!!!

One of my favorite things to do at the drags is watch the flowerglide guys get all flustered when you pull them, grabbing gears all the time, and they lose track of THEIR car and pull the big breakout!!!!! I'm one of them nasty guys that just loves to run-em-out on the big end!!!!!!

Truth is, it's almost scary just how consistent a five speed car can be when you get yourself and the car working right!!!!!! Skids, you'll have to come around and make a few passes in the lil Bronco II when I get it done!!!! You'll go home and throw rocks at them slushboxes!!!!!!

Originally Posted by MGONCHAR

What would be nice to clarify would be in a street race what would be better. For example, if you are going 40-50MPH the Th400 would be in 2nd gear with a much lower gear ration then the 6 speed in 2nd. Wouldn't the same car with the 6 speed excellerate a lot faster?

The main thing to consider and always remember in a stick car is the RPM range for your peak torque----then use that stick coming up out of the floor to keep the engine in that range!!!!!!!

Originally Posted by MGONCHAR

What would be nice to clarify would be in a street race what would be better. For example, if you are going 40-50MPH the Th400 would be in 2nd gear with a much lower gear ration then the 6 speed in 2nd. Wouldn't the same car with the 6 speed excellerate a lot faster?

All things equal yes... With some dependence on how good you are on the clutch

Put a Gear Vendors OD on the TH400 and you get a thrifty 6 speed automatic. You control the OD unit with a button on the shifter. Problem is cost. $2500 for the OD unit ................

Kitz