My newly restored '71 442 has the original th400 trans and whatever axle ratio came standard with an a/c car (3.08 or 3.23+/-, I think). The car runs around 3000rpm at 70 on the highway. I would like to have a lesser engine speed. I know I could go with a 700r4 or a 2004r overdrive unit. I have been seeing some info on the Gear Vendor's Overdrive unit. These are evidently tough overdrive units which are also pretty pricey ($2500+). They have a gear redution factor of .78. Have any of you folks had any experience with this unit? Thanks.

 

I have seen then installed in long wheel base pickup trucks, they take up a lot of room don't know how they would work in the tunnel confines of a car. If your car isn't a daily driver it seems like a lot of expense. Have you thought about a different ratio rear end. It would be a lot less expensive. Even a built overdive transmission would be less expensive and take less modification then an overdrive unit. Just my opinion

 

The installation is straight forward. It bolts on and replaces the tail housing.. It is longer so that it will require shortening the drive shaft. Depending on your vehicle it may require a little messaging of the tunnel.....The company is very helpful if you need help. When finished you actually have a six speed.
1st, 1st overdrive,2nd,2nd overdrive and 3rd, 3rd overdrive. Or you can put it in automatic mode and it is just an overdrive after 3rd......As you said they are bullet proof goood to 1200 horsepower.....If it were mine to do over again I would purchase a BUILT 200r4 and use it.....Nothing bad to report just hard to justify the cost/benefit ratio.....As many have said before.......If you are not going to drive your car 3000 plus miles a year then why do either.........

 

Thanks for the advice. I plan to keep this car and drive it a good bit. I just took it on part of the Hot Rod Power Tour with my friend who has a '67 Chevelle with a 5 spd Tremec. He was doing about 1700rpm at 70. The GVO would pay for itself over a period of time and I feel more comfortable with the engine operating at a lower rpm. I also hate getting rid of a good th400. Thanks again.

 

I've only heard good things about Gear Vendors. I have considered purchasing one of their overdrive units for my Oldsmobile in the future. It is pricey; however, it comes with a lifetime warranty as long as you own the unit.

 

If you spend $2500 to make the change and you get a 3mpg increase - you drive 5000 miles per year, it will take you 17 years to recover the money. The rest has to come from peace of mind.

 

700s hav gm pattern not bop pattern like the 200 does

 

yup, the 200 is the only overdrive that'll fit the olds without an adapter plate.

 

No, 700R4s have a CHEVY pattern. BOP patterns are also GM.

 

So.. what is the difference in hp/torque/gearing capabilities of 200R and the 700R?
As I understand it 700R's are based on a TH350 and the 200?
Also the 4L80 is based on the TH400. Is the only advantage to a 200R is the BOP pattern? What are the high performance applications of the 200R other than the Buick GN? How much can they be built to handle? I'm looking to tow in a 400hp/500ftlbs 68 vista cruiser.

 

Neither one in stock form will be able to handle that kind of output. I think most people prefer the gearing of the 2004r. i have a 200 that I will be putting in my car once my build is complete. Both can be built to handle that kind of power, but from what I've seen the 200 build up seems to be a little more pricey.

 

How much HP/torque are you running, redvette?
If the car is a big block slower than 13 flat in the quarter mile, I'd just use a 700r4 and an adapter plate.
If it's a small block in the same range, you probably won't break the 700r4.

Just my opinion. 700r4 has great gear ratios.

 

The 700 R4 works well if you have a rear end ratio in the low threes (i.e a 3.08, 3.23, 3.36, 3.42, maybe a 3.55), because it has a deeper first gear (3.06) than the 200-4R (2.74). If your rear end ratio is a 3.73 or anything numerically higher, the 200-4R is probably a better choice than the 700-R4. There is more to the equation than rear end ratio, though; your rear tire size, how you intend to use the car, if your engine is "soggy" on the bottom end or has great low-end torque...

Gear Vendors makes a good product, although I have heard some complaints that under spirited driving conditions, you can't rely on it kicking into overdrive immediately when you flip the switch. For highway cruising this would not be an issue, but if you are using it for racing it could be a headache. I don't have any personal experience with it, that is just what I have heard from more than one source.

 

This post is old and I still have not put anything in the '71 Olds. I must before the Hot Rod Power Tour in June. Ms.(for me) to Iowa to Al.! The 700r4 is probably the best way for me to go. I have same in a '69 Camaro and it sure makes it a better driver. The engine in the '71 is all stock. Rebuilt .30 over with a mild Melling cam (smooth idle). Balance, blueprinted, decked, line bored, etc. Very smooth, dependable but 3k at 70mph is still too much for me. My hot rod buddy has a '67 Chevelle that he has put a Tremec 5 speed in and a 3.55. He is doing 1900 at 70. I can't let him get too far ahead of me! At age almost 61 you tend to want quite and cold a/c (or at least that is what is happening here). I will get going on this pretty soon. Bowtie Overdrives sells these 700 units for what appears to be a resaonable price. Perhaps I will do that. Thanks for the advice. Mike

 

You can't go wrong with an overdrive. I'm sure you will be happy with it. Keep us posted.

 

I have a Gear Vendor in my 69. It is a bolt in, but does require some minor "massaging" of the floorboard for clearances. It doesn't shift quickly into overdrive, but it is a throttle sensitive shift, meaning the harder your in the throttle, the harder it shifts. If the car has a TH350 now, the 2004r will bolt in using your existing driveshaft. If towing is in the future, rebuild the trans with a hardened input drum (the stock one is a well known weakness) and premium clutches and wide band. Use a good shift kit (Trans-Go or CK Performance are the best IMO) and install the largest trans cooler you can find. Make sure the TV cable is installed and adjusted correctly.

 

Has anyone tried installing the gear vendors overdrive with a stock 4 speed? Their website suggests that would be their strongest suit.

 

I think that you should look into a used unit for cost purposes . I have one and it is not for sale plus these units wear very little with proper maitanence.

 

Did you mean rebuild the 200r4 for towing? I know a 200r4 can be built to handle horsepower but what about towing? I know one needs to tow in 1:1 gear anyway so could it handle it?

Al

 

Yes, use the same upgrades as if you were going to race it. Use the biggest trans cooler you can find. The 2004R is a good trans with the correct upgrades. If I was in the same position now as I was when I installed the Gear Vendor I would seriously look into a 4L80E trans. The price on the trans controllers has come down, they now have bolt-on extension housings that accept a cable driven speedometer, and can handle some serious power.