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View Full Version : th350 to a 700r4 ?????



1981silverz28
03-31-2005, 07:32 PM
I have an 81 camaro with a mild 350 /th 350 and unknown rear gear ratio.The car turns 2500 rpm at 55 mph with a 25.7" tire ,so I think 3.08 rear??? I want to swap in a 700r4 and 3.73. What am I going to need to put this tranny in?? i was told by a shop it would go right in no mods except shorten the d-shaft.Is this true? Do I need a stall or stock or like a Saturday night special??Thanks

myclone
04-01-2005, 05:54 PM
While I havent performed this swap myself Im thinking that shortening the drive shaft and possibly moving the crossmember rearward some is about all you need to do on the mechanical side. There are sites that show the dimensional differences of various transmissions (hotrodders.com forum has a sticky on it I think).

The 700R has a really deep first gear so I would start out with a stock stall if your engine is built to make torque and isnt cammed to the moon.

Be absolutely sure that the 700R4s TV cable geometry is set up correctly on the carb end to actuate the TV valve (there are kits available to do this). If its not death of your 700 will come soon.

chicane67
04-01-2005, 08:47 PM
350 to a 200-4R would be a much better choise.

1981silverz28
04-07-2005, 06:44 PM
What are the adv. of a 200-r4 over the 700-r4 ?

Steve Chryssos
04-08-2005, 03:42 AM
Closer 1-2 gear ratio and a better overdrive ratio .70 for the 200-4R vs. .76 for the 700R4. 200's can be built to handle a lot of power. And if the 700R4 spins your wheels, you should step up to a 4L60E. And 4L80's can handle decent power stock. So basically--use anything BUT a 700R4. I've never met a 700R4 that I liked. They made sense a coupla years ago, but not so much any more.

myclone
04-08-2005, 05:14 AM
Closer 1-2 gear ratio and a better overdrive ratio .70 for the 200-4R vs. .76 for the 700R4. 200's can be built to handle a lot of power. And if the 700R4 spins your wheels, you should step up to a 4L60E. And 4L80's can handle decent power stock. So basically--use anything BUT a 700R4. I've never met a 700R4 that I liked. They made sense a coupla years ago, but not so much any more.


I agree with what Steve said that if you want the most durable 4spd OD trans that is somewhat affordable on a mere mortals budget then a properly built 200R4 would be a better choice really. The down side is that there are only a hand full of ppl that I know of that can properly build one compared to almost being able to buy rebuild kits for 700s at walmart. The Buick Grand National guys have went low 10s (maybe high 9s) on built 200s and the only way a 700 will stay togeather going that fast is in the trunk of a low 10 second car.

The gear spread on a 700 between 1st and 2nd is horrible compared to a 200 but I doubt youll really notice the diff between the .70 and .76 OD between the two though. If youre making lots of low end torque then the 1-2 shift isnt too awfully bad in the 700 but if your engine is peaky in hp/tq a 200 will be easier for you to keep the engine in the RPM sweet spot.

If your car is mild and really more of a driver/weekend car then either trans will work fine but if you flog it at the track regularly then the 200 has advantages IMO. Picking up a turbo buick BRF unit would be the quickest way to get a desirable 200R4 but be prepared to pay out the nose as that is the unit everyone is after.

The 4l60e isnt really a huge leap in durability (its basically an electronic 700R4) but they are a little better since the factory addressed some of the durability issues they had with the 700s. There is the added expense of the control unit for a 60E unless you want to go full manual shifting which you will HATE on a street car/driver after the first few times stuck in stop and go traffic.

The 4l80e is a brute of a trans and the only thing more beefy from GM is an allison which I doubt would fit anyways. The 80e is factory rated at around 600ftlbs and is basically the old reliable TH400 with OD added as well as electronic controls (like the 4L60E). This trans is over kill in just about any mild street car that is normally aspirated IMO but youll be hard pressed to break one no matter what you throw at it if its healthy to begin with. The down side is that its a HEAVY unit (80lbs heavier than a 700) as well as requiring a pricey control unit to run it. These units arent cheap to purchase either as they can easily exceed $3000 for a rebuilt unit plus $600-$1200 for the control unit unless you go full manual valve body (which youll hate).

To sum it up:

weekend/driver with occassional WOT blasts=700R4 or 200R4
make more than ~450ftlbs of tq and flog it at the track a every other weekend=200R4
regular track floggings without worry and high tq numbers=4L80E

astroracer
04-08-2005, 07:59 AM
Not to pick nits but the 4th gear ratios are .67 for the 200 & .70 for the 700... Not a noticeable difference if you ask me.
Trans 1st 2nd 3rd 4th Reverse
Powerglide 1.76 1.00 1.76
TH350 2.52 1.52 1.00 ___ 1.93
TH400 2.48 1.48 1.00 ___ 2.00
200r4 2.74 1.57 1.00 0.67 2.07
700r4 3.06 1.62 1.00 0.70 2.29
4L60E 3.06 1.62 1.00 0.70 2.29
4L80E 2.48 1.48 1.00 0.75 2.08
The real difference is 1st gear and a low torque motor will like the 700 better...
Mark

Ishmael
04-08-2005, 05:44 PM
This might be of some help: http://www.chevyhiperformance.com/techarticles/94038/

vintageracer
04-08-2005, 06:21 PM
The other reason for a 2004R is that it is the same size as the 350 you are removing. IE you will not need a new drive shaft. You can use your original drive shaft. A 2004R will BOLT IN where you 350 now lives. It's also a better transmission. If you look for a core or one to have built, the GN unit is the best with a unique valve body. Second best is from a Monte Carlo SS or 442 from the 80's.

1981silverz28
04-11-2005, 11:52 AM
Thanks a lot !! It looks like i will be on the lookout for a 200-r4 in the near future.Again thanks!

patriot68
05-02-2005, 01:49 PM
get a gear vendors unit and be done with it..the 350+gear vendors od unit can take a whole lot more than a 700 or a 200
scott

toxicz28
05-02-2005, 02:12 PM
The other reason for a 2004R is that it is the same size as the 350 you are removing. IE you will not need a new drive shaft. You can use your original drive shaft. A 2004R will BOLT IN where you 350 now lives. It's also a better transmission. If you look for a core or one to have built, the GN unit is the best with a unique valve body. Second best is from a Monte Carlo SS or 442 from the 80's.

Forget looking to a 442 or a GN for a donor transmission. You would need one from a Monte SS because of the bellhousing, or you'll need to find an adapter plate. The trans my buddy pulled out of his Monte only had a v-8 Chevy bolt pattern .

zbugger
05-02-2005, 02:24 PM
The other reason for a 2004R is that it is the same size as the 350 you are removing. IE you will not need a new drive shaft. You can use your original drive shaft. A 2004R will BOLT IN where you 350 now lives....
Sorry, just a little misinfo here. The 200-4R will not just BOLT IN. It requires moving the crossmembr back a few inches. I had a custom one built for me when I did the swap. Yes, you can re-use the stock driveshaft.

Also, yes, a TH350 with GV is good, but it takes up a lot of space. That means that you may have to open up the driveshaft tunnel a bit to get it to fit. Then you also have to shorten the driveshaft quite a bit and get it re-balanced. Add to it the price of the GV being the same price as a complete new OD trans, and you got a big cost ahead of you.

Oh, and I may be wrong, but the bellhousing is a dual bolt pattern on mine. I think it may work with a GN trans. Just don't hold me to it.

derekf
05-24-2005, 05:58 AM
Ok, back to the top for this one..

It may be time to replace the TH350 in my Elky with a 2004r.

Being cheap (since I am cheap) and broke (since the wife is not cheap) the 4-figure prices I'm seeing for rebuilt trannies are probably more than I need to be looking to spend... so it looks like junkyard tranny is the way to go for me.

Given that I've never rebuilt a transmission, is this something that I can/should be trying to rebuild on my own or is it a task that really needs to be farmed out?

If it is indeed something I should be able to do, is there a recommended guide/manual for it, and what parts should be upgraded while I'm there? (and if I'm replacing all those parts, is the donor car that important any more? It's a safe bet that my 396 won't ever put out much over 400hp.)

What should I expect to pay for a complete pull out 2004r? (obviously, prices will vary by region.. but I'd hate to get ripped off)

Daves 69
12-08-2007, 08:55 AM
Hi everyone, new to this site. I had the 350 TH and a short block 350 and I just put in a new 700R4 behind my new 468 hp 396. I had to shorten my drive shaft. I had to modify my cross member since some had already modified the cross member. I am still looking for the right cross member. This is for a 69 chevelle Malibu. Any that knows where I can locate it, please let me know. I did put in a new Stalh converter, B&M shifter and ladder bars. I had to put on some street legal slicks to obtain as much traction as possible. I am not happy with the low end shifting but I like the 4th gear overdrive for high end since I have the 411 pos rear end. I wished I would have known about the 2004R before but this is always a work in progress. I also had to move the cross member back to one factory hole and drill an additional hole.

nekkidhillbilly
12-12-2007, 01:47 AM
Forget looking to a 442 or a GN for a donor transmission. You would need one from a Monte SS because of the bellhousing, or you'll need to find an adapter plate. The trans my buddy pulled out of his Monte only had a v-8 Chevy bolt pattern .

all the 200s i have both chevy and bop bolt patterns on them

in not adapter plates are like 30 bucks