I was just seeing if i could get some opinoins, im overhauling my car and i wanted to try to put 400 to 450 to the wheels without power adders, now i dont know which trans i want to use, the car was orginally a auto, i bought a TH350 but i know it will suck up alot of power, been thinking about it for days dont know what to do.

 

i know the TH350 is the 2nd strongest trans gm makes how does the 700r stand up to the 350?

 

does anyone have any suggestions?

 

I got a TCI 700r4 and I am putting out a dynod 375hp on motor and I am spraying with a 150shot on top of that and the trans is just as tight and shifts just as good as the day I bought it. If you read some of the threads on here though there is a guy named Dana that everyone is pleased with...I would get a 700r4 from him. 700r4 you can run 373's 411's and the overdrive you can still drive on the highway with out your tach bouncing off the revlimiter at 60mph.

 

It really depends on what you want. On average, to build a 700r4 to hold the same power as a turbo 350 will cost you more, and a 350 to hold the same power as a 400 will cost you more. The 400 is a beast of a trans that you wouldnt need for that amount of power, unless you want a transbrake, it will also rob more power from your setup. 350 is a nice trans which is relatively cheap, but doesnt hold up well to transbrakes. Only advantage of the 700r4 is the overdrive. If you want the overdrive and have a little bit more money to throw into this go 700r4, if you dont care about the extra gear and are focused on racing or a cheap budget go 350, if you want a trans brake, massive hp, or a very cheap stock trans, go 400.

 

I agree with everything except the transbrake and t400 part

I would substitute bulletproof 2004r for t400.

You can get a 700r4 that will take your power for the same amount of money as a 350 when you add in stuff to make it fit. Crossmembers and torque arm mounts aren't free, and your time is also worth something.

Ebay will net you a 700r4 for less than a grand that will just fall into the car like it was supposed to be there...

 

I'm not familiar with the 2004r except that it's a trans grand nationals use. But wouldnt u need a custom crossmember for that?

Very true about the stuff to make the 350 fit, I wasnt really taking that into account, probably should have. Texan did say he already had a 350, I just kind of figured he had the crossmember and stuff to go with it.

 

There really is no difference in what it takes to fit if you do not use a 700r4. Even with a T350 you can match it to the proper length so that you re-use your original driveshaft.

You need a custom torque arm mount, that is the pricey part if it's aftermarket and new.

It's reasonable enough nowadays that it doesn't make much sense to use anything other than a 700r4 if you're in the less than 500 hp range and running an automatic. It just doesn't cost that much to upgrade them now.

 

I really appreciate all yalls input, i heard alot of people running 700r4, like i was saying i wont have more than 400 to 450hp, i did have the TH350 already but i got it real cheap from a friend but it the one with the long tail shaft which i know i will need a custom drive shaft made, right?

 

Nope, 350 long tail uses the same shaft as the 700r4

 

i found this what yall think

This car would feel 166 pounds more torque with the Th-700R4 transmission then a TH-350 in first gear and 178 pounds more torque than the TH-400 in first gear. To have the same torque multiplication with the TH-350 or TH-400 we would have to run a 3.73:1 rear end ratio. Now with the TH-350 first gear of 2.52 x 3.73 = 9.40 x 100 lbs of torque produced by the motor = 940 lbs felt at the tire. Also the TH-400 first gear of 2.48 x 3.73 = 9.25 x 100 lbs of torque produced by the motor = 925 lbs felt at the tire. If you have any Hot Rod blood running through your veins, this has to sound like fun running around town on Friday night. If you were looking to lower cruise RPM we just went the wrong way with this example. Running a 3.73 to 1 rear end gear ratio sure won't help gas mileage or lower your cruise RPM down the highway. With a 26" diameter tire and 3.73:1 rear end with the transmission in 1 to 1 third gear like the TH-350 or TH-400 in high gear, your engine would be turning approximately 2889 RPM at 60 MPH. This is not a pretty picture!
Solution
Install a TH-700R4 with these existing 3.08 rear end gears. This car will launch like a TH-350 or TH-400 with 3.73:1 rear end ears, so you can now have your stop light fun. When the Th-700R4 goes into fourth gear, your final drive ratio will be 2.16:1. (3.08:1 rear end ratio x .70:1 4th gear ratio in the Th-700R4 = 2.16:1 overall final drive ratio) With a 26" diameter tire, a 3.08:1 rear end ratio and the Th-700R4 in .70:1 fourth gear, your engine would be turning only 1670 RPM at 60 MPH. This is a pretty picture!

 

^^^ fairly acurate, except they don't mention the fact that a 700 has a steep 1-2 step, being 3.06 low gear, 1.62 second. Thus, it has it's own faults. You will need more than a stocker for the power you're looking at, but you'll need more than a stock T350 too. Look at Pro Built(Dana) and PATC(raptor) for a high-quality reliable 700R4/4L60.
A t350 would require an aftermarket tq arm mount if you are planning on running the stock tq arm, but for performance use and with either trans I'd reccomend going to an aftermarket remote-mounted adjustable tq arm.
All the power in the world does you nothing if you don't build the chassis/suspension to handle it.

using a 2004r in place of a t400? You lost me there. We've got a couple T400's in 2000+hp blower cars running well into the 4's in the 1/8. There ain't a 200 alive that will take that.

 

so the 700r4 has the mounting spots for the torque arm and the TH350 dosent right? When my motors done its probably going to have 430 to 450hp and the crank. Also will the th350 suck up more hp than the 700r4? I know what ever one i use i will have it built up.

 

I think they both take about the same amount...
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I was basing that on the 6 second GNs out there...

 

A 700 can be built up if done right to handle that hp. So why not stay with the 700?

 

so which you think is the best trans? i would like to have a 4 speed but i know the TH350 is a good trans. They both cost about the same to have built, or buy one that can handle 450hp, my friend wants to buy my TH350 for his truck so im trying to decide to sell it and get the 700r4?

 

Definitely sell it and buy a 700r4.

You will save more money because you won't have to have any special parts to make it fit.

The only specific piece you need is a tailshaft housing for a third gen with the torque arm mount bolt holes cast into it. They are a dime a dozen at the wrecking yards.

 

alright thanks!!

 

I'd highly reccomend buying a trans built by a reputable shop. Many(most) local trans shops really don't have a clue when it comes to building a truely stout 700r4. You don't want to do this again do you?

btw - the 700 takes less to pull 1-3 than a t350.

 

I couldn't agree more. Talk to Dana at Pro Built Automatics. He's an expert when it comes to building the 700r4, and his trannys have held up in 10 second drag cars. He's more expensive than the Ebay sellers, but worth every single penny extra.