T56 vs TH400
Thread Starter
10 Second Club
Joined: Jun 2002
Posts: 1,884
Likes: 4
From: H-town
T56 vs TH400 i was thinking of going with a 400 in place of my M6 soon. i would like to know whats going to happen. the car is a 02 SS with a 3450 race weight and best et of 11.88 at 118 with a 1.88 60ft.
now on an average
1. just about how much mph will i lose?
2. just about how much better will my 60's be?
3. how much longer will a 10bolt with 3.73s last behind it?
4. and most importanty, on an average, considering i did not have a problem shifting the T56 and with nothing else done to the car, how much will i gain or lose in ETs. this is considering that i was getting every thing out of the T56 as possible.
what do yall think?
Steve.
now on an average
1. just about how much mph will i lose?
2. just about how much better will my 60's be?
3. how much longer will a 10bolt with 3.73s last behind it?
4. and most importanty, on an average, considering i did not have a problem shifting the T56 and with nothing else done to the car, how much will i gain or lose in ETs. this is considering that i was getting every thing out of the T56 as possible.
what do yall think?
Steve.
The Bull
Joined: Jun 2002
Posts: 3,578
Likes: 2
From: Grand Rapids, MI
1. Lose? You might actually gain 3 to 4 MPH.
2. Substantially
3. Longer then with your M6, but less then you would like
4. ET you might gain .5 sec or more
When I made the switch it was a night and day difference. I didn't skimp on the parts that were used. The only thing that is a pain is watching the engine spin some RPM's on the freeway compared to the six speed. Overall, it is a great switch for racing.
2. Substantially
3. Longer then with your M6, but less then you would like
4. ET you might gain .5 sec or more
When I made the switch it was a night and day difference. I didn't skimp on the parts that were used. The only thing that is a pain is watching the engine spin some RPM's on the freeway compared to the six speed. Overall, it is a great switch for racing.
Thread Starter
10 Second Club
Joined: Jun 2002
Posts: 1,884
Likes: 4
From: H-town
a .5 sec gain will sure be nice but it sounds unrealistic for a high 11 second car. although i might be wrong. also i was almost sure that mph would be lost with an auto. right now, my best mph is a 119.70. how much did you gain on the 60' and were you useing a transbrake? i will not be useing one.
The Bull
Joined: Jun 2002
Posts: 3,578
Likes: 2
From: Grand Rapids, MI
My car on motor is not that impressive. Mid to bottom 11's with the TH400 and upper 11's with the 6 speed. A lot of that has to do with a converter rigged for nitrous and some other stuff. But it's a reasonable comparison. I gained .2+ on the 60'. It just comes out of the hole nice and consistent every time. The six speed was way more tempermental with getting going. I've done it with and without a transbrake. My preference is with the transbrake.
And for the other side of the coin...
Beef up the drivetrain, throw a stout clutch in there (Ram VDS/910 here), get some ET Drags, a 2-step & gears, and you can 60' with the autos. Of course, you have to be willing to dump the clutch at 6000+.
And you have to be ready to break stuff, or buy parts that are break-resistant (like a spool, beefy torque arm, beefy driveshaft, etc).
Autos are definitely more consistent, but for me, I'm neck deep in 6-speed parts - I build my own, and have my own spare parts. I don't build autos - I'd have to rely on someone else's work, and I don't like the thought of that right now. 6-speeds are SO much easier to work on.
Beef up the drivetrain, throw a stout clutch in there (Ram VDS/910 here), get some ET Drags, a 2-step & gears, and you can 60' with the autos. Of course, you have to be willing to dump the clutch at 6000+.
And you have to be ready to break stuff, or buy parts that are break-resistant (like a spool, beefy torque arm, beefy driveshaft, etc).Autos are definitely more consistent, but for me, I'm neck deep in 6-speed parts - I build my own, and have my own spare parts. I don't build autos - I'd have to rely on someone else's work, and I don't like the thought of that right now. 6-speeds are SO much easier to work on.
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TECH Senior Member
Joined: Nov 2001
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Originally Posted by taqwache
a .5 sec gain will sure be nice but it sounds unrealistic for a high 11 second car. although i might be wrong. also i was almost sure that mph would be lost with an auto. right now, my best mph is a 119.70. how much did you gain on the 60' and were you useing a transbrake? i will not be useing one.
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I went TH400 for awhile, hated it.
Was boring at the track even with a manual valve body, pulling the front wheels on the transbrake was fun but after the launch it bored me.
Its a pain on the street. alot of people don't care but i couldn't handle it, never wanted to take the car out, I've put more miles on my car in the last 3 weekends with teh new motor and six speed back in it than i did in many months with the th400. i hated doing 50 mph and being at 3000 rpm. and that was on 28" tires,too.
at the track it kicked ***, sure..sixties were good, totally dummy proof to launch and was consistent and strong.
but i agree with camaroholic, you can get the same results from a six speed if you make the time and investment to do it right. i now have a D&D Performance trans, spec stage 3i clutch with billet flywheel and i already had the best of everything suspension/tq arm/rearend/driveshaft wise before going back to six speed so no concerns really about breaking anything. I launched the car twice on slicks sunday nite on the street at over 6000 rpm and didn't even faze anything in the car.
i know i'm very glad i went back to six speed, drive it anywhere and its 100 times more fun to race than the 400 was, i had an A4 Firehawk last year as well and racing that thing was like taking a nap. would have been more fun with a big stall i'm sure though.
Was boring at the track even with a manual valve body, pulling the front wheels on the transbrake was fun but after the launch it bored me.
Its a pain on the street. alot of people don't care but i couldn't handle it, never wanted to take the car out, I've put more miles on my car in the last 3 weekends with teh new motor and six speed back in it than i did in many months with the th400. i hated doing 50 mph and being at 3000 rpm. and that was on 28" tires,too.
at the track it kicked ***, sure..sixties were good, totally dummy proof to launch and was consistent and strong.
but i agree with camaroholic, you can get the same results from a six speed if you make the time and investment to do it right. i now have a D&D Performance trans, spec stage 3i clutch with billet flywheel and i already had the best of everything suspension/tq arm/rearend/driveshaft wise before going back to six speed so no concerns really about breaking anything. I launched the car twice on slicks sunday nite on the street at over 6000 rpm and didn't even faze anything in the car.
i know i'm very glad i went back to six speed, drive it anywhere and its 100 times more fun to race than the 400 was, i had an A4 Firehawk last year as well and racing that thing was like taking a nap. would have been more fun with a big stall i'm sure though.
oh and if anyone tells you that a stock 10 bolt will last 30 seconds with a th400 and a huge stall like i had(4500 yank) they are nuts, maybe footbraking it with a smaller converter and a drag radial or something, but that's about it. put a slick on it and it'll be kaboom time.
TECH Senior Member
Joined: Nov 2001
Posts: 11,603
Likes: 0
From: Chi-Town, IL
My car used to be a 6-speed........I was having problems w/the trans and clutch, so I decided to give the TH400 a try.....
Car was very consistent........driving on the highway isn't fun, I don't do it anymore and will not with the new motor/supercharger setup.......
Its awesome on the street for cruising, the manual valvebody makes it more interesting......
10-bolt won't last long especially off of hard launches, especially if you have a T-brake, its hard to stay away from that pull cord....
I do miss the highway cruising parts of the 6-speed, but when its comes to all out drag racing, the TH400 is for sure the way to go........
Car was very consistent........driving on the highway isn't fun, I don't do it anymore and will not with the new motor/supercharger setup.......
Its awesome on the street for cruising, the manual valvebody makes it more interesting......
10-bolt won't last long especially off of hard launches, especially if you have a T-brake, its hard to stay away from that pull cord....
I do miss the highway cruising parts of the 6-speed, but when its comes to all out drag racing, the TH400 is for sure the way to go........
The Bull
Joined: Jun 2002
Posts: 3,578
Likes: 2
From: Grand Rapids, MI
TH350's work well in lighter cars, sub 3200 pounds mostly. TH400's can take the abuse of a much heavier car without the need to go and rebuild it as often, if ever. It's really up to each individual, but dollar for dollar the TH400 has traditionally lasted longer with fewer issues. That is not to say that you cannot get a TH350 to do the job. Just that the TH400 is more popular for people concerned about the weight of their car and the reliability.
Originally Posted by DERTY
TH350's work well in lighter cars, sub 3200 pounds mostly. TH400's can take the abuse of a much heavier car without the need to go and rebuild it as often, if ever. It's really up to each individual, but dollar for dollar the TH400 has traditionally lasted longer with fewer issues. That is not to say that you cannot get a TH350 to do the job. Just that the TH400 is more popular for people concerned about the weight of their car and the reliability.
before I choose one or the other. 
Thread Starter
10 Second Club
Joined: Jun 2002
Posts: 1,884
Likes: 4
From: H-town
thanks for all the responses. i already have a farily new TH400 that i ran in another car in the past, and considering the price to get my 6-speed to hook, looks like a TH400 is in the near future. hopfully i will gain the same that most of yall are. that would make me very happy. about the streetablity of it, i was already use to it in my old 69 so i dont care about that.
Thread Starter
10 Second Club
Joined: Jun 2002
Posts: 1,884
Likes: 4
From: H-town
one more ?. with a short 26" ET street tire, what gear would be best. i already got 3.73s right now and wanted to keep them to help the axle live a little bit longer but i will go to 4.10s if that is what will work best.
