What is the main differences in these two. Which one runs better on long hauls. I putting in a 350 with LT1 intake and was wondering which one would be best suited for my car.

 

the 700 has an overdive. it's a 4 speed compared to the 3 speed th350. 700 is best for everyday driving, you'll get better gas mileage.

 

Thanx, thats what I thought. A friend of mine was telling me to get the th350 because it would last longer than the 700r4. Who makes a good aftermarket 700r4??

 

The TH350 has a better gear ratio and is lighter. The 700 is a good street tranny. The low first gear will get you off the line quicker and the OD can let you run taller gears in the diff.

For a daily driver street vehicle go with the 700. For any sort of a race vehicle go with a TH350.

Both can be built to take abuse but the TH350 would be cheaper to build up.

 

Steve put it best. I run a Turbo 350 in my Daily driver with 5500-6000 rpm shifts @ WOT and a 2500 RMP conv. I plan on racing it all this season but it will be my daily driver too. Overall, I can't say anything bad about it. I've been taken off the line by a few thirdgens but when it starts to pull and the 700 guy makes the 1-2 shift it looks like they are standing still. I don't race on the road but have done a few stoplight takeoffs to about 30-40 mph.

-Matt

 

I am verey happey with my th-350

 

I want to run this past you guys:

I was told by a local parts store that the 1981 Malibu came with an OD TH-350. Is this correct? If so then we could have the best of both worlds !!

 

No such thing as an OD turbo 350. Theres a turbo 250c/350c that has a lock up torque converter. I don't think any GM cars had automatic overdrives in '81.

 

200R4 had overdrive. Dunno what year, but before '84 i know for sure.

 

I like the 700R4 alot more than TH350 or TH400.

What rear end ratio are you running?? Where does your engine make power at?

Final drive ratios:

700R4 with 3:42's

1st gear, 3.06+3.42= 6.48.
2nd gear, 1.63+3.42= 5.05. 3rd gear, 1.00+3.42= 4.42.
4th gear, 0.70+3.42= 4.12.
Most TH350's

1st gear, 2.74+3.43= 6.16.
2nd gear, 1.57+3.42= 4.99. 3rd gear, 1.00+3.42= 4.42.

As you can see the your going to get more throughout the gears and have that extra 4th gear for cruising.

A th350 is a stronger tranny from the factory but a 700r4 can be built to hold just as much and offers more punch.


SSC

 

Your math needs much to be desired. You don't add the tranny gear ratio with the differential gear ratio. They're multiplied.

700R4 with 3.42

1st = 3.06x3.42 = 10.46
2nd = 1.62x3.42 = 5.54
3rd = 1x3.42 = 3.42
OD = .7x3.42 = 2.39

TH350 with 3.42

1st = 2.52x3.42 = 8.62
2nd = 1.52x3.42 = 5.19
3rd = 1x3.42 = 3.42

The TH350 has a much closer gear ratio. Why do you think all the older muscle cars wanted a close ratio 4 speed? That close ratio allows the engine to stay in a smaller power band. Although the TH350 won't have an effective rear ratio lower than 3.42 like the 700's 2.39, it will pull through the powerband better.

The 700R4's deep first gear will create much more torque mutiplication. This really helps getting a heavy car moving however that huge jump to second gear loses too much in the rpm drop. Putting 3.73 gears with the 700 makes things even worse. The first gear torque multiplication should overpower most street tires without even trying.

That's why the 700R4 is a good street tranny. It will get you moving quicker and give a highway gear while in OD however WOT shifts are it's downside.

 

Ok I see a couple of mistakes besides the improper format.
But the general idea was there. Where did you find the Th350 ratios at that you have?? I was told that they were the same as the 200c's except for a few that had numericly high (low) 1st and second gears.



Its still a learning process, I learn something new every day. This board is very helpfull.


SSC

 

probuilt makes a nice 700r4 tranny unfortunatly i cant remember the website but someone should be able to help you out.

 

Gear ratios on these transmissions are as is:
TH400, 2.48 - 1.48 - 1.00
4L80E, 2.48 - 1.48 - 1.00 - .075
TH350/C, 2.52 - 1.52 - 1.00
200/C, 2.74 - 1.57 - 1.00
2004R, 2.74 - 1.57 - 1.00 - .067
700R4, 3.06 - 1.63 - 1.00 - .070
The quickest/fastest OD is the 2004R. If you already have the 700R4 do not change it out for the 2004R, not worth the expense. If you do not already have an overdrive then the 2004R is the way to go, if feasible.

 

Thanks for finally posting the correct ratios. The above posts were kinda scary. In a street car the ratio difference won't make much difference. Even with 3.73's and a 700r4, you can launch just fine--you just have to control your right foot. Most streetable engines put out enough low end torque so that the extra rpm drop during the 1-2 shift makes no difference. The only question you need to answer is: Do you want to pay the extra money for an overdrive.
If you are building a 'race' car, the th350 has better ratios for a high hp engine that has a narrower powerband. It's also cheaper to 'refresh' every season.

 

Pro-built's website is www.pro-built.net:) .

 

How much would it be 2 swap in a 2004R from a 700R4? Is there any info out there on such a swap. I was wondering if they use the same TV cable and where 2 get a cross member.

 

does anyone know what is the average top speed for a turbo 350?