I've read alot about swapping my th350 with a 200R4 or a 700r4, and I'm leaning towards the 200r4 due to gearing. I'm curious why the 200r4 costs more than the 700r4(I thought it would be the other way around). Additionally I'm not sure about what would be a good stall speed. My car is mainly a street car, powered by a strong 350. I see alot of 2k or higher stall converters and I'm curious as to how streetable this would be, or if I should stick with a lower stall speed. My rear gears are 3.08's at the moment and want to maintain freeway abilities.

Gearing is something I know nothing about, but want to make sure I get it right the first time

I think a 3.73 gear is just about perfect with the 2004R. Excellent freeway manners, and great around town. My converter is rated for 2200 stall. Seems fine to me. If I were a drag racer, I'd shoot for a bit more. Depends on your motor and its torque curve.

Make sure your cruising speed in O.D. is above your stall speed and make sure your stall speed is in the power range of your cam.

The 200-4R used to be less money and considered less desirable and not as strong. That is until a few years ago when people finally realized that the same upgrades people where doing to the 700R4 would also beef up the 200-4R. Now the 200-4R seems to be the trans of choice for hot rodders because of better gearing, with better fitment and easier installs. As for stall speed it depends on how your motor is built to make power. What is the cam intake heads ect. As a general rule I would probably start with a 2000-2200 stall with a lock up converter.(see bottom of page) The lock up converter will help on the highway with those 3.08's it will keep you in 4th and keep the trans from building excess heat from slipping. If you want gears that are more fun around town and still good for cruising try 3.55's or 3.73's. For example I have been running my 220 with 3.73's for several years now and with a 26" tall tire at 65mph I cruise at just over 2100 rpm. Which is slightly lower than the 700 and without the big rpm drop from 1st-2nd like the 700 has.


200-4R forth gear torque converter lock-up switch. All you need is one hot wire to the transmission. No computer needed. Fits 1981-1993 transmissions. Cost $45.00



http://www.transmissioncenter.net/4th_LockUp.jpg

Make sure your cruising speed in O.D. is above your stall speed ....

Hate to disagree, TJ, but that's not an issue with a lock-up converter.

Interesting Al, I was told not to go above your stall speed. Learn something new every day. Thanks.

You would have to "go above your stall speed" at some point or the car would never move. Stock torque converters are set for the 1,500 to 1,800 RPM range (Corvette has the highest factory stall). A 2,400 RPM stall isn't much if anything above stock and they usually they stall around 2,200 anyway. The only reason to buy one in this range is to get the benefits of their higher quality due to fully brazed turbine blades, and fully rollerized parts.

The advantages of a looser converter are a car that acts like it has a clutch. You can leave the stop light at a higher RPM if you so desire with nothing more than a foot break (say up to the 3,400 range). If you don't want a higher launch speed, or say the wife is driving, the only thing you will notice is if feels like the tranny is slipping a little as you try to gather up speed when driving it "normally". The advantage comes with the locking converter which will lock up as soon as the line pressure in 1:1 (3rd gear) trips the switch. No more slipping transmission feeling, responds like a clutch car while cruising.

There is more heat generated by the higher stall (looser) converter and I would recommend a heavy duty transmission oil cooler, because of this but otherwise it is a win win situation. I personally think a 3,200 to 3,600 RPM stall (stall speed depends upon the amount of torque your engine produces) is perfect for the street. Of course I have never in my life attempted to calculate what my gas mileage might be because I consider performance paramount (well maybe safety comes before performance but it would be a close call either way).


Larger Dave

I bought my 2004R from CPT Transmissions and after talking to Art, he said not use a lockup converter, something to do with the way the converters were designed, I cant remember now something to do with heat and EPA?. But in a nutshell they are not needed. He also told me that the 2004R can be built allot stronger than a 700R4 which I believe after blowing 3 Level 3 700R4s from a popular builder here.

3.73s and 200-4r . . . ever drive the old monte SS? . . . perfect

using a 2800 hughes 11" lock-up (was gonna put in '86 t-type) in the '68 and I like it, but it's a lil small for the cam

running a 3600 9.5" lock-up in '94 Z and have no problems w/ driving anywhere . . . so don't let that steer you

match your combo up and you'll luv it

I bought my 2004R from CPT Transmissions and after talking to Art, he said not use a lockup converter, something to do with the way the converters were designed, I cant remember now something to do with heat and EPA?. But in a nutshell they are not needed.

In my opinion the lock-up feature is excellent. It's kinda like having a fifth gear, and great for fuel economy if that's important to you. It can also be switched off if you don't want the lock-up, but I think for a car that is primarily street driven it's a nice feature to have.

And for what it is worth I run a lock up converter in my sled Impala with a 3600 lock-up converter behind a 582 BBC. I've only paid for one converter so far (going on two years). I'm probably stressing it more than you would ever think of stressing it and it's holding up on the street (9.17 last outing at the 1320)


Larger Dave