turbo 400 vs 700r4

[Kid Racer]

hey guys i know that the 7oor4 is better butevery one tells me they r because of the over drive in it i mean does it really go that much faster on top end the the turbo 400 tranny

[deadtrend1]

What?

Th-400's are better cause they are stronger, not cause they lack overdrive. if you want to go faster on top end, put higher gears in the rear.

[NJSPEEDER]

overdrive vs non-overdrive isn't about how fast it can go really. foot to teh floor the 700R4 will only go into 3rd gear anyway. teh difference is having the overdrive to make it more livable on the street and get better mileage when rolling down the highway or really anyplace that you spend time above 35-40mph.

there is really no reason to get rid of the 700 unless you are planning to build an all out race car. even then, a th350 or powerglide would likely be the better choice.

[WayFast84]

Originally Posted by deadtrend1

What?

Th-400's are better cause they are stronger, not cause they lack overdrive. if you want to go faster on top end, put higher gears in the rear.

I thought If you put lower gears in the rear you have more top speed. Higher gears more acceleration? Or is that what you mean and I just dont understand it.

[deadtrend1]

Originally Posted by WayFast84

I thought If you put lower gears in the rear you have more top speed. Higher gears more acceleration? Or is that what you mean and I just dont understand it.

lower = 3.73:1
higher=2.73:1

think about going in 4WD low and not being able to go fast.

[Fast92RS]

Originally Posted by NJSPEEDER

overdrive vs non-overdrive isn't about how fast it can go really. foot to teh floor the 700R4 will only go into 3rd gear anyway. teh difference is having the overdrive to make it more livable on the street and get better mileage when rolling down the highway or really anyplace that you spend time above 35-40mph.

there is really no reason to get rid of the 700 unless you are planning to build an all out race car. even then, a th350 or powerglide would likely be the better choice.

IIRC the 700r4 can go into overdrive at wot if it has that servo(not sure if thats what it is called) for a corvette.

[WayFast84]

Originally Posted by deadtrend1

lower = 3.73:1
higher=2.73:1

think about going in 4WD low and not being able to go fast.

I got you. thanks alot.

[Tru2Chevy]

Originally Posted by Fast92RS

IIRC the 700r4 can go into overdrive at wot if it has that servo(not sure if thats what it is called) for a corvette.

No, that's just a shift servo that helps it keep line pressure up between shifts.

There is another part that you can replace (name escapes me at the moment) that will allow you to adjust how much pedal pressure you need before the trans will drop from 4th to 3rd.

- Justin

[deadtrend1]

Originally Posted by Tru2Chevy

There is another part that you can replace (name escapes me at the moment) that will allow you to adjust how much pedal pressure you need before the trans will drop from 4th to 3rd.

this?

[98tadriver]

Originally Posted by Tru2Chevy

No, that's just a shift servo that helps it keep line pressure up between shifts.

There is another part that you can replace (name escapes me at the moment) that will allow you to adjust how much pedal pressure you need before the trans will drop from 4th to 3rd.

- Justin

I believe the name is-- 3-4 upshift valve or something. i bought one a few years back for my turd gen, but never got around to installing it. Cops had that option in their cruisers i believe, and i think the older corvettes might have but dont hold me to it

[98tadriver]

Originally Posted by Kid Racer

hey guys i know that the 7oor4 is better butevery one tells me they r because of the over drive in it i mean does it really go that much faster on top end the the turbo 400 tranny

dude, you need to associate yourself with some smarter car people! dont believe anything that "they" tell you. The guys on the boards here know their crap fo sho

[Tru2Chevy]

Originally Posted by deadtrend1

this?

Yea, that's it. I've seen ones that won't downshift until ~90% too.

- Justin

[Kid Racer]

yeah i now my pop is an top a mechanic.and he would always lie to me about things so i stop asking him...thanks guy you guy have helped me alot....

[Mike]

that makes absolutely no sense. why would your pops lie to you and have you buy parts that arent as good?

[johnjzjz]

an over drive converter is not designed to go to lock when the TV cable connected to carb or TB is pulled all the way out, in a simple explain the excessive oil pressure stops the Governor from allowing it to happen -- its a little more involved than that but you get the idea -- also the 400 trans was the choice for GM with big block motors from the 60s making 375 to 600 HP in some cases, the 700 trans was GMs choice for fuel economy and low performance engines - just so you under stand the lock up in the converter uses the stater support on the front pump to take the load on its splines and after a while they the splines wear causing the vibration and or the odd bump you feel when it locks up, the 400 on the other hand is a bull dog it can take a wild beating and still give good service for a long time -- heaver and takes more power to use -- jz

[camaroracer1992]

i have a race prepped 700r4 for sale with convertor if youre interested. Just freshened up from last year, 0 miles on it. asking $1300 with convertor, its built to the top of the line raptor specs

[BonzoHansen]

Originally Posted by cbrrmike

that makes absolutely no sense. why would your pops lie to you and have you buy parts that arent as good?

Wait till you have a kid, LOL.

[Pampered-Z]

Are you just asking for knowledge or are you planning on changing trans for a reason?

The OD trans are good for most street cars and for adding some highway gas milage, but will not support the big power a Turbo350 or 400 will. From what I've seen a well built 700 also cost more then a 350/400 trans.

Once you're making big power and hooking hard you will want a TH trans which would have stronger internals and case. "I Think" most use TH350 in place of a 400 on small blocks mostly becuase they can withstand the power and cost less then the 400, but someone can correct me if I'm wrong?

personally I look at glides as track trans. Those I know that run glides are really pure track cars and do so because with it higher first gear to calm down a car (wheelie prone), consistancy, or are in lighter cars. I don't know anyone running a glide in a heavy car for other reasons?

One other option is to use a TH trans and a external OD unit such as a gear vendor. This allows you to use 350/400 trans and still have OD. The down side is your adding weigth to the car and cost and another stress point for failure into your drive train. But I've seen it done.

I based this about a street type car, where crusing around 2,000 RPMs on the highway is as important as low ETs. If you build a car for racing then you're going to build the gearing and suspension, trans, convertor etc. into the total package and give that more importance over driving down the highway at 3,000RPMs.

[BonzoHansen]

Build a 4L80E and get a TH400 with OD!

[Fast92RS]

Ive seen th350 swaps into a third gen but can you do a th400 swap into one, with the toruqe arm and all?

[BonzoHansen]

Originally Posted by Fast92RS

Ive seen th350 swaps into a third gen but can you do a th400 swap into one, with the toruqe arm and all?

They used to make a swap kit, but I have not seen the th400 one in a while.

[Kid Racer]

no i was asking because i didnt now...all i now is when i had my camaro i had a 700r4 and i had to rip it out 3 times before i rebuilt it with a b&m street fighter rebuilt kit for it..then it was a bad a&& tranny....but i have always heard that 350 and 400 trannys were better then most trannys...and to answer some of u guys ??? about my dad is...he doesnt tell me the tructh cause he doesnt want me to race or to getinto cars like that....so he trys to keep me away from working on them and puting better parts and adding more power to stuff he doesnt always lie to me but sometimes he does....

[unstable bob gable]

In this day and age there is no reason ya can't get an O/D tranny to work in just about any application. I love my 200R4s!

[johnjzjz]

Originally Posted by Pampered-Z

Are you just asking for knowledge or are you planning on changing trans for a reason?

The OD trans are good for most street cars and for adding some highway gas mileage, but will not support the big power a Turbo350 or 400 will. From what I've seen a well built 700 also cost more then a 350/400 trans.

Once you're making big power and hooking hard you will want a TH trans which would have stronger internals and case. "I Think" most use TH350 in place of a 400 on small blocks mostly becuase they can withstand the power and cost less then the 400, but someone can correct me if I'm wrong?

personally I look at glides as track trans. Those I know that run glides are really pure track cars and do so because with it higher first gear to calm down a car (wheelie prone), consistancy, or are in lighter cars. I don't know anyone running a glide in a heavy car for other reasons?

One other option is to use a TH trans and a external OD unit such as a gear vendor. This allows you to use 350/400 trans and still have OD. The down side is your adding weigth to the car and cost and another stress point for failure into your drive train. But I've seen it done.

I based this about a street type car, where crusing around 2,000 RPMs on the highway is as important as low ETs. If you build a car for racing then you're going to build the gearing and suspension, trans, convertor etc. into the total package and give that more importance over driving down the highway at 3,000RPMs.

Gm installed the powerglide in every car they sold from shoe box novas to vettes to 4000 pound impalas SS cars with all the bells -- the 375 HP 396 chevells were the fastest street cars ever built 65 / 67 with powerglides, high gear is the same 350 400 and iN A glide, its all one to one / and today a 350 does look Heavy duty compared to 700 and alike real steel drums and solid alloy servos and clutch pistons compared to pressed plate like making a dish or spoon yea it works but it has an end not like the others - powerglides today can handle 2500 HP of coarse they are not gm cases but some stuff in them is still OEM original 30 year old components from the original cars they came in -- jz

[Ian]

Originally Posted by Fast92RS

Ive seen th350 swaps into a third gen but can you do a th400 swap into one, with the toruqe arm and all?

spohn has a cross member and torque arm for that swap.