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]

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]

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]

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]

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]

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]

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?
(http://store.summitracing.com/partdetail.asp?autofilter=1&part=TCI%2D374400&N=700+115&autoview=sku)

[98tadriver]

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]

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]

this?
(http://store.summitracing.com/partdetail.asp?autofilter=1&part=TCI%2D374400&N=700+115&autoview=sku)

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]

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]

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]

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]

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.

[Batman]

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!


That is what I'm talking about! that is the least expensive O/D transmisson that can take a real beating

[BonzoHansen]

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!

I agree, I'd use that over a 700R4 or it's later cousins anyday. Or the 4L80E for real brute force apps.

[WildBillyT]

That is what I'm talking about! that is the least expensive O/D transmisson that can take a real beating

Yep. A lot of the guys I've seen with real high dollar high hp automatic "street" cars use a 200.

[Pampered-Z]

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

yes very true, I never had the furtune of a BB back then. So when i think street car and glide I tend to go back to my 283 cars backed with the slip and slide, forget the gear ratio in the rear, I think the 64 impala shifted out of 1st around 65MPH, right before the traps. :mrgreen:

[johnjzjz]

yes very true, I never had the furtune of a BB back then. So when i think street car and glide I tend to go back to my 283 cars backed with the slip and slide, forget the gear ratio in the rear, I think the 64 impala shifted out of 1st around 65MPH, right before the traps. :mrgreen:

P.O.S. Nutech 383 with spun bearings and destroyed Callies crank!


i just read that and i have seen many many callies cranks do just that we think its in the metal ( rockwell ) < its hardness was incorrect and sheared off the bearing material and everone we sonicked was cracked a year old -jz

[WildBillyT]

P.O.S. Nutech 383 with spun bearings and destroyed Callies crank!


i just read that and i have seen many many callies cranks do just that we think its in the metal ( rockwell ) < its hardness was incorrect and sheared off the bearing material and everone we sonicked was cracked a year old -jz


Speaking of poor rockwell hardness,

John, did you run across a problem with some of Comp's Cams being too soft a little while ago?

[johnjzjz]

Speaking of poor rockwell hardness,

John, did you run across a problem with some of Comp's Cams being too soft a little while ago?

i have had the pleasure of watching thousands of dollars and countless hours re doing some one Else's mistake -- all the out sourced stuff is up for grabs on hardness and quality - we found the rollers and the cam were the same hardness < only works for a while - and soft crane cams drove me crazy for a few years they fixed it right away but new old stock a year or 2 later always seemed to pop up in a job and boy does that suck on the bottom line - anything can happen to a high end motor that matters to everyone the owner and the shop - but a total piece of crap with sand in the oil runs forever you know what i mean -- jz

[87Fbird]

B&M makes one and Hurst makes the swap kits for TH350 and TH400 in third gens. You can use the stock crossmember and stock driveshaft for the TH350 and the kit for the 400 comes with a crosmember to adapt to the difference in the length. But you'll have to have your driveshaft custom. The kits come with torque arm adapters and all the hardware you'll need. It's all bolt in too.