i am having troulbe deciding on what transmission to use. i am build a street strip 88 camaro with a wild 555bbc. i am hoping for an honest 800hp/700tq + 200shot Nitrous. I was going to do a t56 (either a magnum of tranzilla), but realized that they are expensive and are easy to break when drag racing.

i would really like the OD of the 700r4, but can it handle the power. i have no experience with auto's, but i keep hearing that an auto is better for really high HP.

i don't plan on putting really big tires on the car. the car is lighter than most - stripped, no P/S, a/c, changed to an aluminum fuel cell, no back seats, very minimal thing in the engine bay. i am hoping to be right around or under 3000lb before i get all the safety equipment in.

i have a moser 9" with a 4.11 gear and a locker. the th400 will be like 4200rpm at 75mph, i couldn't do that. i guess it would be about $1500 for a new center section with some sane gears (3.08). but i really can't afford the $6000 tranzilla t56 set up either just to have it break on a lauch.

the 700r4 has an OD, but it is a smaller tranny. Pro Built automatics has one that they say is good for 750+hp. would that be alright since i don't have a super heavy car?

i am looking for good 1/4 miles times (9sec), but still be able to cruise without going crazy.

any insight would be good, or anybody with high hp cars that run the pro-build auto's.

 

a t56 may live behind that kind of power, if its either well built or a magnum t56, the rest of the drive train would be prone to breakage with high rpm neutral dumps,and if it will hook-up,
a 700r4 wont survive long

 

I would go no less than a t56, or a th400 if you cant drive. 700r4 SUCK. I dont care who gets mad, they are sorry transmissions for performance same as a t5.

 

im a fan of the tko-600 ... but thats just me..light weight and can handle a ton of power.and yes 700r4's suck

 

of the three transmissions the T56 would mostlikely last the longest STOCK, but if you build either one of the autos they will be the best for straight line. The TH7004r is not very good stock but when built they are very very good transmissions and with the 4 gears the ratio is alot better then the 3 speed TH400. I would hope with the hp you are running you will have any of them built.

 

do a faceplanted T56 or a th400 with a grear vendors overdrive.

good reading over here... http://www.gearvendors.com/hrgm3s.html

 

It's actually "faceplated"

http://www.libertysgears.com/faceplate-proshift.htm
http://www.ls1tech.com/forums/manual...ain-shaft.html

327sleeper88: Depending on your budget and skills, You can build an upgraded synchronized T56 that can handle gobs of TQ, out of stock parts.. If you abuse the shifts on the track, the faceplated trans would be a better choice, but otherwise read on:

http://www.eecis.udel.edu/~davis/z28..._Fbody_T56.pdf

 

i have a 700r4 and its fine...racing or daily driving

 

is it behind a 800 horsepower 555ci big block with a 200 shot?

OP, what about a 4l80? its an overdrive and much more robust than the 700r4/4l60's. Its a big trans, but its another option

 

of course not, i only have a stock 305 but im putting in a 461 stroker so i will upgrade the trans

 

an of the above options will be built. i was over at ls1tech and they had a huge forum over a t56 vs th400 for an 800 hp turbo motor, and the majority said th400. there were even people breaking viper spec and tranzilla t56's.

the reason i don't want a 4l80e is the weight, size, and the HP it robs. also, don't they need a computer to control them?

I am going to attempt a dual 4" exhaust on the car, so i need as much room in the trans tunnel as i can get. i know the t56's take up less that any auto, but 4l80e's are big.

A member by "greezmonkey" runs a th350 behind his 496bbc, drag only, and runs mid 8s on n20. isn't a 700r4 on the same playing field size-wise as a th350, and 4l60e? i really need an OD gear.

the 200 shot may not happen right away, but the motor is build with that in mind.

I had a TKO 600, but sold it to my dad with a 383 stroker. i have heard or people cracking the case on TKO's with even less hp/tq than i have. a tko would have been fine for a street-only set up.

i was thinking about face-plating, but that takes driveability way down, and its Mucho $$$$.

 

I do recall a friend of mine running 30lbs of boost with a Kenne Bell on his 03' Cobra. Those come with the MN12 T-56(stock). He was making around 900hp and that thing held up like champ.

 

x2

or, since 6>4, what about a 6l80e? sounds like you have a little bit of coin to spend, talking about godzilla and magnums and all that nonsense.

 

I'm running a slightly beefed ( clutches mostly ) th400 behind my wildcat in a 5800 pound truck.
I've broken 4wd hubs, ripped out U-joints, and such, but the trans just keeps on keepin' on !
Yeah, it's a little lossy as far as power to the wheels, but since I'm after torque and not HP, it works for me !
Then, too, a stock th400 can still be found in many bone yards for reasonable, even cheap, compared to building anything to handle the stresses.

 

4l80e's and 6l80e's are a bit big for me. also, there isn't much aftermarket support for them, and when there is they aren't cheap ($5000-$8000). in stock from, they are good to about 500ish hp before they start to fail.

i am sure that a stock t56 will survive street use even with the power im making. but when it comes to drag racing with sticky tires, manual tranny's get put to the limits.

how many street miles would a face plated t56 last before needing a rebuild? street miles for me is like road racing.... hard on gas, then hard on brake...

 

spoke to a couple of transmission builders over the weekend, in Orlando for the World Street Nationals and both of them told me that 500hp/470+ trq is the max limit a 700r4 will take when its used as both strip/street,(more strip) they both told me I should go to a th400, (yes I would lose a little drivabilty, sans the OD) option were to go with a th400 and add a gearvendors OD unit, or a 4l80e and get a stand alone electronic controller for it.

th400 built and with a gearvendors OD @ $3600
max built 700r4 is @ $1500 +/- , most people usually go through 2 before getting wise
add in roughly 6-800 for a billet style convertor in the 32-4000 stall range

 

Question... do you really need 4.11 rear gear with that motor? What size tires will you be running and whats the peak hp rpm of the motor?

800 hp will trap 135-140 in a typical thirdgen. With 28" tire and milder 3.42 gear, thats 5540 rpm thru the traps at 135 with no converter slip. I assume peak power on a 800 hp 555 will be in the mid higher 6000 rpm range? 28" tire/3.42 gear isnt a bad option.

On 200 shot look to trap 150-155. Thats 6160 rpm with no converter slip on 28" tire 3.42 gear.

Near 3080 rpm on the highway at 75mph.... still high but possible to do.


T56 will last if you dont beat on it too much with sticky tires and such. I"ve seen them live for long time however behind some very fast cars. Use a clutch that will break/wear out first before the trans and that will keep the T56 lasting.

 

Haha a true drag racer... 1000hp on tap and still worried about parasitic drivetrain loss! Well this one is easy...

A lot less gear no matter what you run

If you're well funded a 4L80e with a good billet converter and a Microsquirt to control it (under $400 for everything you need)

If you're sticking to a budget then a 400 with a good billet converter

 

i got the rear end with those gears in it, and also with plans of a t56. I think ill be making peak power at 6800-7000, depending on cam choice.

something else i was thinking... with this much power and a semi-light car, could i get away with a 3.08 gear with a th400?

this is on a different topic, but with is the max tire size able fit in a stock wheel well? i don't have any plans (yet) to mini tub or back halve the car.

i am new to automatic tranny's, where would be the best place to get a billet torque converter? what stall would you guys recommend?

 

Yes. I have 2.73's turning a 26" tire behind my 800+ hp boosted sbc and it will light ET streets up at 50mph in third gear.... Its rather intense. I dont know what i'd do with more gear but the car is setup to use that highway gear with the engines power band and trap speeds so far.

With 7000 rpm power... you'd like to be in the 4.11 range with 28" tall tire to take advantage of your motors power in the 1/4 mile. Say a 140mph trap speed with 800+ hp, thats 6900 rpm with 28" tire. On spray, you'd want 3.73's for around 6940rpm and 155 mph traps. Not exactly sure what speed to expect but I can imagine another 200hp on top of 800 with the motor will give 10mph more traps.

For a street car compromise, the taller highway gears 3.08 or so will give up ET but still beable to work. 140 traps on that is 5176 rpm. So your down almost 2000 from optimal but gain much more performance on the street during cruise.

With T56 that double overdrive makes those 4.11's act like 2.05's in a Th400. Thats the advantage of 6 gears.

 

im thinking i will just go with a th400 and give it a try with the 4.11's my first drive with the car will be on the street, and im sure that i won't be able to hook in any gear.

good thing is i can buy a new center section for street driving, and then swap the one i have now when i go to the track. i could get a 3.00:1 with a tru-trc for the street, then use my 4.11:1 with a locker for the track.

i have all the tools to change the gears, so i might just swap the gears out and see whats what.

Orr89RocZ, where did you get your th400? what kind of converter are you running?