im looking into some automatic transmissions. its a toss up between a th350 or th400. if done alot of searching and i have the basics on the two. my car is going to be street/strip car. the car is going to see alot of track time next season. im leening more towards the th400. is this over kill for my car. the th350 would be nice because it is lighter but i think the extra weight of the 400 is worth it. i know that i want a manual valvebody. is there any benifit with using a reverse manual valvebody. im also think about a transbrake. my motor make 576hp and i might run nitrous later down the road. so i need a trans that can handle about 650-700 hp at the crank. i would also like to know how to pick the right stall converter. im also runnig a currie 9inch with 411 gears. any suggestions are welcome. im no trans expert so please bare with me on this. thanks alot

dan

 

built TH400 with all the upgraded goodies inside and a Tbrake is a nice setup for you. Go with a nitrous stall as well from coan, etc and know that you'll have $1300-2000 into the trans alone when you're done.

 

i talked to the guy i work for on weekends(streetrod building and fabrication). he is the one that would be getting me the trans. he gets really good prices form a very reputable company. he said that the 350 would be better for me. he has a 1932 ford 5 window coupe with a 750-800hp 434sbc and he uses a 350. he has a manual valvebody with no trans brake. his car is a thousand pounds lighter than my car. thats the only thing he said might stop me from using a 350. he said that he will talk to his trans guy and see what he thinks would be best for my application.

 

TH400, these things are too heavy for a TH350 trans with high horsepower and nitrous like you're planning on running. Besides transbrakes for a TH400 are hella cheaper than TH350 transbrakes. You'll thank me later. A T bucket compared to a thirdgen is like saying you have a rail car instead of a tank.

 

do the th400s fit in a third gen with out modifing the trans tunnel

 

if you put a scattershield around the trans then you will need to modify it slightly, if you just put the trans in then it fits.

 

the guy whos going to build my trans would be using those really really thick aluminum sfi aprooved bellhousing(if thats what you call it). would that clear.

 

probably need to do a little cutting and welding, not a bad job really, we put a TH400 in there with a really big and thick scattershield around it in case the converter let go and had to cut out little strips from the tunnel and weld in boxes, took maybe 2-3 hours with beers tossed in the mix. Plus it was my first time mig welding as well, luckily the carpet covers up the floor there along with the dash.

 

Did you ever think about using a 700r4.. easier boilt in, get the better gear ratio, and keep the OD.. It can put a 3800lbs car well into the 10s.. ck it out www.700r4.com Also great info on choosing the right TQ

 

yeah i though about a 700r4 but i really dont think that it could withstand the power and beating. although the overdrive would be very nice.

 

Is not the 700R4 just a Turbo 350 but with overdrive?

 

What do tou think this vehicle will weigh? What has been done to the motor? Any super or turbocharging? Nitrous? What kind of times would you like to see? I have 700R4's & 4L60E's in the 9's & 10's doing fine. Let me know if I can be of help?

 

the car weighs 3600lbs with me in it and im 200lbs. the motor is N/A with no power adders(i dont think im going to run nitrous). i need a trans that can handle about 600hp at the crank. if i can use an overdrive trans that would be awsome. im looking to go high 10s at the track

 

The good news, is that the 700R4 can do this pretty well. The torque converter stall will depend on what is done to the motor, the rear end gear ratio, the cam duration at .050" lift, the lobe centerline, head work & compression ratio, and how you drive, etc. Let me know?

 

ok thanks. ive got some info on the motor for you. it makes 576hp@6200rpm
and 582ft-lbs of torque @ 4600rpm.

ill give you the info i have.
-gross lift .594/.594 (or @ .050 .3060/.3960
-duration @ .050 is 252/256
-intake centerline is 107.0
-lobe separation is 107.0

the heads are 227 brodix aluminum heads. they are cnc machined and my compresion ratio is 10.5:1.

my rear end has 411 gears in it.

my driving style is pretty mild. i dont beat the **** out of it all the time but deffinately dont baby it.