700r4/200-4R guys: was it worth doing?

Was it worth the time and money? Happy with the results? Burn one up? Would you do it again? Gas mileage noticably improved(not that it matters). Durability?

I'm considering swapping out my th350. Thanks!

 

All of those parameters depend on one question.... Do you spend a lot of time at highway speeds? If you do, its worth it. If you don't, its money you can spend somewhere else. I have one in my '33 but when I did it, I spent a lot of time on the highway. Now, not so much. My '62 has an OD standard but I needed the 600 ft lb number so its not a waste.

 

I went from a TH350 to a 700-R4 and was happy with the results at highway speeds. The tab was right at $1100.00. I didn't run in OD around town. I was running an injected 355 so the mileage on the hiway was better but around town about the same---

 

Absolutely.

You can build either to hold 400-500 HP, so durability is all about the options you choose and quality of work.

Mileage is a no brainer. If you drop cruise rpm by 30% on the hiway, you score. If you never cruise the hiway and rarely spend anytime above 50 mph, it may not matter.

The two main issues anyone ever has are really the easiest mistakes to avoid. First, wire the lock-up circuit as intended, through the brake switch. It costs about $15 and is so much better than a toggle switch. Second, really get educated about the TV cable adjustment. This is where amateurs burn one up. The TV cable must have a certain preload, operating stroke and depends on the right radius at the throttle lever. Most folks pay little attention here and mess it up. Lastly, there is insurance available now from TCI. They offer a new valve body that eliminates the risk of smoking one due to poor TV adjustment.

 

Three advantages to using a 700-R4:

1) Lower First gear ratio.

2) OD means (obviously) lower rpm at cruise.....less engine wear, as a rule.

3) Because of #2, you generally get better fuel economy.

My take is this: if the car is mostly a local cruiser & around town vehicle....well, you can buy a lot of gas with the money you would spend to convert...it will take quite a while before you even reach the "break-even" point where it was worth it to switch. Though the 1st gear ratio might be of some help, performance-wise, depending on what you have, so that's a factor.

If you do a lot of highway driving, as the others have said, you will probably find the swap worth it.

 

I've had a 700R4 in my '51 Ford for something like 13 years. It's been trouble free and transparent in its operation. Two qualifications:

- My car was originally a Fordomatic, so it has a 3.31 rear end. Seems like a good combination.

- For a while I was annoyed by the shift points, which all seemed too low. I then learned that there are three governors available for these transmissions: passenger car, truck, and Corvette. Mine had a truck governor in it. When it was replaced with one from a Corvette, I was much happier with the shift points.

I'd certainly do it again.

 

Make sure you get an engine set up for the rpm level of the O/D . So you dont have to rev it up all the time to pass someone. That will kill your mileage.
If I were to do a cruiser again Id just have a th350 and less aggressive rear end gears, maybe a tall rear tire and call it done.

 

i have done afew 200r4s i like them, they have offerd good gears ratios for my app. it also has a .63 to 1.0 over drive, well something like that. i have always used TCIs constant pressure or full manual valve body to replace the stock one. the full manual elimanates the TV cable compleatly and makes for a nice install and yess the lock up convertor is a nice 150 to 200 RPM drop at high way speed and if hook up corectly. they are not the strongest transmission by far but with a good book and high quality parts they can be built to last a long time. and lastly i have blown up a few, full throttle shifts with way to high of line pressure and kevlar clutches have separated many a parts from some 200r4s that i have put together.

 

I keep getting told that 700R4's don't like heavy vehicles and tow pig duty.

Is this true?

Sorry to steal the thread for a second but it sounds like there might be a couple people who actually know what the hell they're talking about in here.

 

depends on how heavy and how much towing.

The big mileage increase from overdrive is most noticeable with a medium sized engine (350) and a lighter, more aerodynamic vehicle.

Also the internal workings of an overdrive automatic make it kind of challenging to build it so that it can hold onto a lot of torque with a big load on it. The 200 and 700 overdrives are not real strong in OD, so it's relatively easy to burn them up if you work them too hard.

So...for a car with a mild to moderate performance engine, that you put some highway miles on, it can be worth it. Expect mileage to increase about 30%.

For a truck that you're towing some weight with, especially with a big engine, you're probably better off spending the money on the extra fuel.

 

I love mine

 

What kind of price range do the full manual valve bodies come in at?

 

One of the best swaps I've done. Swapped out the TH400 short shaft behind my tired 350 in my 1970 C-10 running 3.73 gears. So now instead of getting run over by ranchers in the slow lane at 2800+ rpm on the highway I'm at 2300rpm.

I collected a couple 700r4 trans from local gold chainers and friends so the swap cost was minimal and now I have a couple spares. $200 for this donor trans, $110 for the shortened driveline, $68 fluid, filter, gasket, etc, $11 for better pressure switches (I did the wiring myself with PM help of some HAMBers here), moved/reused the th400 crossmember for a grand total of just under $400.

 

I think its well worth it. I recommend an overdrive for all my customers, unless they are doing a pure restoration, or a track-only car. If you already have a TH350, a Th2004R is a bit easier/cheaper to swap in. Use a Monte Carlo SS core, or, if you can find one, a Buick GN core. They are all dual pattern, so it will bolt up to Chevy or BOP. You will have to move the crossmember back, or in some cases make a new one, but the driveshaft doesn't have to be changed. One of my customers has an OT '78 Vette with a 330hp 350 crate engine, with the factory Demon carb and headers and 3.36 gears, and its gets about 23mpg on the highway, and according to the customer "feels" faster than before. He had a reverse manual valve body Th350 beforehand.

The question you need to ask yourself is not how often you drive on the highway, but how often would you LIKE to? The above mentioned Vette was once an around town cruiser...now, he drives it anywhere and everywhere, and instead of sitting in the garage most of the time the car now gets driven.

 

About towing... the 7004R is rated to approx. max. 900lbs trailer weight (of owners manual)...and not use of the O.D. gear.... (in a G30Van)
Learned this when wanted to make a tower of an GM 6,5 Diesel /7004R..
many companys could deliver for power & performance with lot of hp., but when wanted it stronger without changing hp, to also keep some towing, then they couldn\t deliver.......

 

The way I look at it is if you spend 1200 on the conversion. with the fuel you save it will eventually pay for itself. This is dependent on how much highway driving you do.

Just be careful setting up your TV cable or you can burn one up in a hurry.

 

Fuckin' A it was worth it. 2004R will allow you to keep existing TH 350 driveshaft but you'l ll have to relocate the tranny mount. I flipped mine around and it worked.

You'll never look back. I run 3.70 to 4.10 rear ratio with 28"-30" rear tires - I have a couple of these installed - one 2004R and one 700 R4. It's not about the fuel saving so much as about the vastly improved driveability - faster out of the hole and more relaxed on the Fwy.

 

I went with a rebuilt 200 4R and 2.73 rear gear with a manual lock-up switch under the dash at 70 mph RPM 2100 flip the switch 1700 RPM car wanted to lug when I dropped down to 60 with the torque converter still locked up and I had to remember to shut it off. Got 22 mpg took 2004R out because it just seemed to lug anytime it was in 4th gear below 60 mph and had very weak shifts ,put a TCI turbo 350 in and still I get 21 MPG when I keep my foot out of it. I had all intentions of putting a 3.50 rear gear just never got around to doing it when the 350 came up at a steal so I just swapped it around I like alot better than the 200 4R....... just my experience....

 

Milage increase is minimal, but you gain a ton in drivability. With the first gear of a 700/200 and 3:08s is almost like launching with a th350 with 4:10s.
If you dont already have them, its best to go up to a 3:42 or lower rear gear. To keep yourself in the power band.

 

The question should not be whether to go with od or not. If you have a driver it's the only way to go. The 700R4 or 200 4R difference is just a matter of gear spread. The 200 4R is like a close ratio manual trans so it works well in light cars. The 700R4 has a very low first gear (3.06:1) so it works well with heavier cars. Either piece can be built to live with about 500 to 600hp. With either trans we have found that rear end ratios from 3.42 to 3.73 work well for street use. About towing, I have an OT Silverado that's my DD. In tow mode the trans shift points are changed and it won't even go into od. The trans is a 4L60E which is basically a computer controlled 700R4.

 

I guess I'm a slow typist. Exactly what spity said.

 

couple of posts mention how much more they cost vs expected gas mileage gain and how long it will take to recoup your investment.

I figure the first time I do 80 MPH @2200 RPM it will be money well spent. my old chevy must have had 3.73's out back. I'd be doing 3000 + RPM's on the freeway and people would be passing me. not sure of my speed since my speedo was way off.

 

Ttt

 

No offense, but with that little girl gearset you don't need an overdrive. Put a set of 3.36-3.73s in it and your opinion will be much different. The factory usually offered 3.42s or 3.73s with performance applications of this transmission.

 

Swapped one in my 62 Chevy c10 p-up, loved it!! would roast the tires with the low first gear and cruise with the traffic on the interstate with no probs.

 

Contrary to popular believe not all 350 to 700 swaps require a drive shaft change, it depends on which length tail shaft the 350 has. I have a 700 behind a 454HO/425hp w/3.42 gears, 3700# cpe. I've pulled as high as 19.6 mpg with the combo. That really makes a difference when you running long distances

 

It all depends on your style of driving. They are expensive for a perf. rebuild, heavy and rob hp but with a lockup and 2.73 highway cruising mpg's you cant beat it. I have spent on rebuild kits anywhere between 600 and 1000 not including the lockup converter price. I used lock and non lockup styles too. In 3 yrs I spent about 2k rebuilding them each time upgrading the different part that broke so in my opinion not worth it. However, if you spend the bucks on all the goodies first time around it will live forever in a 300 to 500hp application. Today, I use a B&M rebuild kit on a th350/3000 stall and 3.42 gears total cost 500 including the converter. To refresh its 100 bucks a year.

 

Ya....Do it!!!!!! I love mine 700 R.....

 

I just did some simple calculations increasing highway mpg by 30%. Let's say you get 13mpg, that would increase it to 16.9mpg. Calculate gas cost (today) at $2.79, you would need to drive just over 22k miles just to break even on a $1100 investment. If you get more mpg now (let's say 15mpg) it would take 26k miles to break even. That's a lot of highway miles boys....

 

bought my 200r4 from danny at AAA transmission in Kansas city (independence mo) $550 said its good to 12 sec. 1/4 mile