Chevy86 IROC-Z

iTrader: (17)

Hi Gents. I have a question.
1. What is the difference between the 350 Turbo and the 700R4?
2.Which is better?
3.And finally, Can a 350 Turbo be stabbed into a 86 IROC-Z?

I was told that the 350 Turbo is not controlled by a TV cable, so can I split the Brake Booster Vac. line and connect it to the 350 T tranny?

89RS_82Z

iTrader: (2)

TH350 is a 3 speed no OD
TH700R4 is a 4 speed OD

350 has less problems, but not as easy on the bank when it comes to cruising since it has no OD

700 has OD, stock its a slush box, but built can be a good trans, mine will bark the tires in 2nd all day long

350 requires a special crossmember thats custom made by you or by a company online or what not, the driveshaft for a 350 is different than the 700 also

Chevy86 IROC-Z

iTrader: (17)

sounds like too much trouble dealing with a 350 Turbo. I think I'll stick with my 700R4. Thanks 89RS_82Z.. Peace

c10crewchief

I think a TH350 with the long tail shaft is the same length as a 700R4 but don't quote me. I am trying to figure out the same with my car and whether having an Overdrive is worth the $$$. Check out this link to find out some FAQ's about 700R4's:
http://www.700r4.com/faq/faq.shtml

c10crewchief

I think a TH350 with the long tail shaft is the same length as a 700R4 but don't quote me. I am trying to figure out the same with my car and whether having an Overdrive is worth the $$$. Check out this link to find out some FAQ's about 700R4's:
http://www.700r4.com/faq/faq.shtml

vangogh4560

the 700r4 has a lower 1st and second gear than the 350 and just stock will rip the tires off in first and second if you would like

bluegrassz

iTrader: (3)

Ok lets see if I can shed some light on this.

The 9" tail housing (long TH350) version is the same length as the 700r4. With the long version, stock driveshaft will work. Even my stock crossmember worked. I did have to buy a torque arm bracket , but thats cheap. You can get the Hurst or the B&M version.

I run 3.73 gears with a 26" tall Hoosier QTP tire. I could run 28" tires on the street and save the Hoosiers for the track. This would take some rpm out and be easier on the street. With the 26" tires, I crank about 3k at 60 mph.

The 700r4 does have a low first gear (maybe 3.06). But the gap between 1st and 2nd is wide. The TH350 1st to 2nd gap is closer together, so you dont have as much rpm drop if you drag racing.

Both trans can be built to hold quite a bit of power. The th350 will be cheaper to build comparied to the 700r4. Also the Th350 weighs less.

It all depends on how you plan on using your car. If its a DD then stay with the 700r4. If its just a hot street/strip and not worried about mpg, then the th350 is a great trans.

Oh yeah, if you do go with the th350, but a double o-ring dipstick like Lokar or a stock one with the boot type seal. Dont ask me how I know. lol

vangogh4560

just some info

3.06:1 First gear and 1.63:1 Second gear found in the 700 are both lower than their counterparts in the TH350 and TH400, providing increased acceleration. The combination of lower First and Second gears and an overdrive cog give the 700-R4 the potential to be a good real-world performance transmission, promising the best of both worlds: acceleration and mileage. The overdrive cog also gives hot rodders the ability to run stiffer rearend gears without unduly affecting fuel mileage at cruising

bluegrassz

iTrader: (3)

Ratio from 1st, 2nd, 3rd, 4th
700R-4 3.06, 1.63, 1.00, -
200R-4 2.74, 1.57, 1.00, 0.67
4L80-E 2.48, 1.48, 1.00, 0.75
TH400 2.48, 1.48, 1.00, -
TH350 2.52, 1.52, 1.00, -
Powerglide 1.76/1.82, -, 1.00,

Everything depends on your use of the car and rear gear ratio/tire size.
Let us know what your plans are for the car.

bluegrassz

iTrader: (3)

The th350 does have a TV cable but you dont have to run it. You just have to manually shift down when you go WOT. With teh correct cable bracket, hooking it up is no problem.

You will need a vac source for the modulator valve. Dont T off the brake booster.

firebird1992

ok now i have a question now i have a V6 with a 700r4
the trans was rebuilt 50000 miles ago now there was a shift kit B&M Stage 1 kit with a 6 fin cooler put on because i was planing on turbocharging (5-8psi) the car

was this the best way to go or would it be better to get the newer 4l60 trans?

i'm also hoping to put a trans brake on it for the track

cronsformula350

I'm going to switch over to a th-350 too, because I don't cruise the car enough to worry about mileage. With a 700r4, a 2400 stall, full shift kit, I get about 150 miles a tank, with a heated oxygen sensor and my true duals, so yeah. I'm going to a th350 soon, with a 3500 stall, the HSR needs it. But until I switch my trans over, I'm going to a 3000 stall. My B&M 2400 only stalls out to 1750ish now, over the 1500 for the Stock TPI, and ported base.

Has anyone found a crossmember you can just buy for the swap? Along with a driveshaft?

Gumby

You can change the gearing.

My Th350 has the 5th clutch plate mod and 3.08 1st gear.

bluegrassz

iTrader: (3)

I did the 5th clutch plate mod also. I kept the stock gears.
I got my rebuild kit from Dana at Probuilt. He even sent a extra steel to ship the pump. It was the first full trans I ever built.

Oh yeah, Jegs have there house brand 10" torque converters at a good price. I picked up a 3500-3800 for just over $200. I even ran across a guy on this board that makes them at there shop.

Gumby

That is one place you don't want to cheap out.

you either use Cohan or TransSpecalties.
coanracing.com
transmission-specialties.com

Why? you actualy get what you pay for in a TC from them.

I use to work in a TC shop and anyone can "build" them.
It so simple it retarted since most are never new just a JY $2-3 core rebuilt which means cutting it open, flushing, replacing a washer or two and a new paint job. [Its a good racket to get into.]


But only a pro shop can get a matched part for your app.
When you order a TC from a real shop they will ask for a build sheet and a dyno run of said engine if you have it. And it will be custom built.
A good TC shop does not make anything until its ordered so its matched for said use / proper. The off the shelf catalog units are all general purpose built and wil be sloppy.

Like crosses
"B&M 2400 only stalls out to 1750ish now"
Cause B&M and other catalog companies just pay 3rd party folks to build 1000s at a time to me sold of the shelf. Which you do not want.

If it cost $200, ya don't want it.

Get a nice tight 10in from a good place and thank me later.

bluegrassz

iTrader: (3)

Yeah, If its for racing I suggest www.ptcrace.com for a custom converter.

If I remember correctly the jegs converter I bought are built by Transmission Specialties. They just box it as there own.

Gumby

Really though you want a good TC for the street more then racings.

If its gonna be street driven too.

That where a lose one will suck

Ya don't want anything that comes pre made months before hand in a box much beyond stock.

cronsformula350

well, I picked up my 2400 for a good deal. But I'm buying a midwest converter from a buddy for $100, its a 3000.

But the great part about the TH350 is that they can build them to hold up to a lot of power, and the gearing spacing, is closer, so the motor stays more in the power band. The 700R4 sucks in a way. The 1st gear's great for torque, but then it goes to 1.75 for 2nd, then 1.00 for 3rd. So it is good for the TPI intake, because it makes a lot of torque to make the trans work well with the TPI setup. But the HSR intake is more suited to a big stall, 3000 or more, along with some 3.70 or larger rear gears for a sweet launch.

If you don't care about over drive either, the TH350 is great. The TH400 has the same gearing, but is heavier and takes some more power to turn, while the TH350 is great for small blocks.

Have any of you that swapped over to the th350 found a crossmember that was prebuilt for us?

bluegrassz

iTrader: (3)

I used my stock mount with my long tailshaft th350. I used the B&M torque arm kit and a poly trans mount.

http://www.summitracing.com/parts/BM...9/?image=large

cronsformula350

I had a friend used a th350, and modified his stock crossmember, but added some parts to it. But A long tail shaft th350 is able to use a stock crossmember for the 700R4?

bluegrassz

iTrader: (3)

Yes with the B&M torque arm relocation bracket. I cant remember if it had a plate for the trans or not. This is in a 89 camaro. Most came with three bolt holes on each side on the body. I cant remember if I used the original holes or one step forward or back.

But yes, I used the stock trans crossmemeber without mods on my setup. Stock TA and driveshaft also.

http://www.summitracing.com/parts/BM...9/?image=large

t5535

I have a turbo 350 in my 87 trans am and the mounts are different to the cross member. you will lose fuel millage with the 350 trans do to the no overdrive. if you are running a carb and not fuel injection at like 50 mph or so when you punch it and open the 4 barrow you can just about watch the fuel gauge go down . If you are gonna drive it everyday or plan on doing some highway driving I would most definitely stay with the 700r. plus one other thing to consider correct me is I am wrong but the turbo 350 uses a gear driven speedo and the 700r uses a pulse (electronic) speedo and there is no way to change that so you speedo will not work enless you go aftermarket. I am pulling my engine and trans this weekend and I havent decided weather I am gonna go back to the 700r or stay with the turbo 350.

cronsformula350

With my current setup, and a heated o2 sensor, and everything working properly with 24# injectors, and other things, I get my 175 miles per tank. I don't care about mileage, I don't drive the car enough to care. So the overdrive is a wash; and the stall will be a 3800, built to handle around 550 horse, and have the converter builtt for nitrous also, incase I decided to spray it. And the only thing that will be a pain, is the speedo, but I can get a converter for that, and my trans is going to have a full manual reverse valve body, so I should be able to use the stock shifter.

But I'm doing my cam swap, dropping in different roller lifters, I thinking about endure-x's. Putting in a 3000 midwest converter and a tune. Should be close to 480 horses. And I also have an aluminum drive shaft to drop in, but then maybe change the trans to.

Gumby

http://www.viragotech.com/fixit/Fuel...encyPower.html

89_camaro

ok so im doin a 700r4 to a th350 swap in my 89 camaro, as far as i know i have the th350 with the 9 inch tail shaft, are you sayin that i will be able to use the driveshaft i have now and the crossmember or what, would u be able to clear it up for me a little bit, thanks

bluegrassz

iTrader: (3)

With a 9" tail shaft, yes you will be able to use the stock driveshaft. It would be a good time to install new u-joints if you havent all ready.

The crossmemeber on my 89 camaro worked. I did use the B&M TA bracket, but I cant remember if it had a plate for the trans mount. I also used a poly trans mount.

http://www.summitracing.com/parts/BM...9/?image=large

89_camaro

will i have to change the location on the crossmember at all? will i have to buy a new TA or just the TA bracket?

t5535

From my experience the cross member will have to be modified. I have a turbo 350 in mine and the cross member does not line up. the turbo 350's mount is further back.

camaromike222

One of our sponsors here makes the crossmember for just about every combo trans you can think of for our cars.

http://www.spohn.net/shop/1982-1992-...GM-F-Body.html

89_camaro

so the spohn trans mont will take care of the TA placement and the mounting issue? would i be able to use the TA that i have know or would i have to buy a naftermarket TA?

camaromike222

Yes and yes, the same TA can be used. I believe BMR and UMI offer a crossmember as well. Just compare prices and do some searches here to find out which one makes the better crossmember. I still need to order mine

t5535

mine was installed when I got the car. it looks like they made there own bracket for it.

89_camaro

awsome thank you...i got one other question, the 700r4 i have in my car now sometime doesnt want to shift out of first gear, if i take it into higher rpm it will shift but most of the time im goin from drive to netural n back to try n shift it. i checked the tv cable, changed fluid n filter, checked the gov and all that is fine, do you know if anything else could be wrong to cause the problem?

Cosmik Debris

If you have a short tailshaft 350 can you just swap a long tail shaft onto it?

cronsformula350

So what other things did you modify? What did you do for the speedo?

bluegrassz

iTrader: (3)

I had to find the correct dipstick/tube. I added a external trans cooler with braided ss lines. Other than that nothing. I had the B&M Mega shifter and had to make sure the shifting cable was in the correct location on the bracket on the trans.

But I did not have to modify my trans crossmember. This is on a 89 chassis and I used the B&M T/A relocation bracket not the Hurst one.

On the speedo, If it is mechanical then you can hook up the cable. If its electronic, you will need a converter box.

bluegrassz

iTrader: (3)

Sorry guys, I thougth I used the Hurst kit, but I think it was this B&M kit.
http://www.summitracing.com/parts/BM...9/?image=large

It says it has a trans mount, so it would realign the mount and the crossmember. I didnt have to modify my crossmember.

You can do a search on both the B&M and Hurst kits.

cronsformula350

Sweet, now I'm wondering if I should bother putting a bigger stall in my
700R4, so I think next summer is a 350 swap. I don't drive the car enough for an overdrive, so TH350, here we go!

cronsformula350

I was wondering, which length tailshaft is on your trans, so that you were able to use the stock driveshaft. I looked into it, and theres a 6", 9" and 12" version, and I don't think you can just swap the tailshaft, because isn't the output shaft different lengths?

So, whos trans did you wind up going with? Because summit has rebuilt units good for 400hp and have manual valve bodies, but they only in the 9" length tails. There are some great TCI tranny's too, but, I need more info on your trans that works with this swap. Because now I have a midwest converter's 3000 stall, that I was told stalls out to 2500 sith a dualplane carb'd 350, thats a 347 horse motor, so in my car, it'll stall higher. But I am tired of the 700-r4, its can be improved on, but the gear spacing holds our cars back, it was meant for a tpi intake, to help with the 1.75-1.00 shift. If you look at my videos on youtube, search for cronsformula350 , and you can see how its like a shortshift, but I didn't mash the gas as hard once it shifted; but it still sucks. Its definitelly not a performance transmission. I wanted to go 6L80E, but thats too much money for right now, but eventually, but by then I'll go to a pontiac old school motor.

bluegrassz

iTrader: (3)

You need a 9" tailshaft TH350 for the 700r4 driveshaft to swap.

rs owner

hey I have a question about trannys I found a couple on ebay with a 1yr warranty the item no.'s are #230394978331 I think this one is for the
F CAMARO 1987 A.T., 8-350 (5.7L) and for the 305 MFI
and the other item number is #290383775806 for
E CAMARO 1988-1989 A.T., 8-305 (5.0L), TBInow I have a 5.0 tbi but in the future possibly near christmas I plan on having a 350/300+hp put in which should I buy in order to not have to buy another which is compatible with both? (street use no racing)
thanx

cronsformula350

So now I am tryin to find a trans rated to at least 450hp for now for 1200$ or so.
I have some buddies with some and maybe they'll cut me a deal.

But for the conversion, can I try the 700r4 speedo gear on the output tailshaft of the th-350?

I also need to buy the B&M conversion kit.

I can use my aluminum 91 GTA driveshaft without a problem, as long as I use the
9" tailshaft also?

What else do I need to do? Buy the conversion kit for the speedo? or perhaps a trans brake?

Anything else?

8t2 z-chev

back in '93 i put a th350 in my '82,if you use driveshaft,
crossmember,and torque arm from an '82 originally
equipped with a th200c or super t-10 4spd,along with
the torque arm mount kit,th350 is almost a bolt-in
(my th350 was from an'80 z28) later,in 95,i decided
to reactivate the A/C,so installed a 700r4 so the A/C
compressor would not be turning so fast on the highway.
used '83 parts to install the 700r4.

sester23

Everyone keeps saying you have to have a special cross member but i put the turbo350 in my 84 z28 and the only thing i had to do was chang ethe tail shaft from the 700 and that's only 4 bolts