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I have three transmissions to choose from, a TH 400, TH 350, and a 700R4 out of an 84 Caprice. The transmission will be going behind a 454 putting out about 450 horse power and over 500lb/ft of torque. The car is a 77 Nova weighing 3700 lb(guess), 3.08 rear end. I am leaning towards the 700R4 because I will be driving it on the highway and I like the overdrive. The car will also see the drag strip on occasion. Will the 700R4 withstand that kind of power? How expensive is it to build any of these transmissions to handle that power?
 

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That is about as the max that trans can take although with 700R4 308 is too much gear.Trouble is lower gear will increase load on trans.If I remember correctly 550 ft/torque is all the case is capable of taking.400TH is best choice but will spin the tires forever with 308 and will be sluggish to get going.Had 455 w/272 ran 14.24 1/4 mile but if started to spin the tires I was done had to be gentle out of the hole top end is was fun.So you have the catch 22.350 simular to 400,400 is the better of the two.
 

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Greetings,

I have a 3.42 posi rear in my car and most people are leaning me toward a TH350 with a stall and heavy-duty shift kit. Supposedly it's stronger than the 700R4 and will work better than a TH400. I'm still doing the research myself though...Can't always believe what others tell you!

Jason
 

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I'd have to vote for the TH400 too. That is really pushing the limits of a 700R4 or TH350. That 3.08 gear is pretty steep for that combination. I would recommend adding a little more gear also.
 

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The 400 was used in all GM's hi perf applications and heavy duty so that will tell which one of those to choose.The trouble with 700R4 is rebuild is expensive to do them right $1100-1500 and if you get the car to hook and case cracks trans is done.I would say 400 with 355 or 373 if your not doing alot of freeway driving.My 2 cents.
 

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The 700r4 will never take the HP and torque at the strip. The 400 is your best bet. The 3.08's will work fine. I had a 73SS with a well tuned mostly stock 350 with 3.08's and it would carry the front wheels about 6" in the air off the line. You'll definitely need good tires and a posi.
 

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That's right on Bigdog I think it will depend on how hard he wants to the car to work at the track.That's what I would make my decision 700R4 just beware at the track low gear,slicks & a car that hooks up with 500ft lbs/torque is border line but street tire reasonable and 700R4 won't be as risky.The 400 won't break under these conditions but u you lose some streetability.
 

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I am running a 700R4 with a 350 engine. One of the reasons I chose my transmission builder is because he was running a 700R4 in a '55 Chevy with a very healthy 427 powering it. I paid $1500.00 to get my 700R4 to the level it is at. He said for $500.00 more, he could build it to stand up to some serious big block power. A TH400 could be built take that abuse for a 1/4 of this cost.
 

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if you are going to spend that kind of money(1500-2grand) why not go with a TH400 and add an electronic overdrive? gives you the best of both worlds. the strengh of the 400 pluss overdrive, plus you not only have overdrive in high gear but in each gear. in other words it turns your 3spd auto into a 6 speed auto check it out! ive never used one, yet, im toying with the idea tho!!:rolleyes:

http://www.gearvendors.com/cg2wd3s.html
 

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A friend of mine had a 454 in his Chevelle and it was making about 425hp and 500lb/tq and he was running the 700r4, it wasent a drag car just a pretty mean sterrt car but he had 3.08's and he would just spin like crazy like anyone with 500fl/tq. He only ran it at the drags a few times with some hard stickies (he would still spin). Im gonna be runing a th350 behind my 454 but I am going to do a shift kit and stronger clutches just to be safe. If your gonna run sticky tires and do some hard launches go with the th400 and forget the overdrive cause it will prob take awile for the extra gear to pay for itself.
 

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I like the OD trans for street driving although you won't like it with a 3.08 gear.
I installed a BTO level 3 200/4R in my car with 3.73 gears and it completely change the car. Had a manual glide with brake prior. After driving it for a while I installed 4.11 gears. My engine is happy now, 2400 rpm @ 65 MPH. For the track just run it through in 3rd gear.
 

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I like the OD trans for street driving although you won't like it with a 3.08 gear.
I installed a BTO level 3 200/4R in my car with 3.73 gears and it completely change the car. Had a manual glide with brake prior. After driving it for a while I installed 4.11 gears. My engine is happy now, 2400 rpm @ 65 MPH. For the track just run it through in 3rd gear.
As old as this is I still can't ignore the misinformation. I have a 700R4 with a 3.08 rear and I can roast the 315 tires at will. My car never stalls or even hesitates, it just boils the tires whenever I want. (425HP)
 

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I like the OD trans for street driving although you won't like it with a 3.08 gear.
I installed a BTO level 3 200/4R in my car with 3.73 gears and it completely change the car. Had a manual glide with brake prior. After driving it for a while I installed 4.11 gears. My engine is happy now, 2400 rpm @ 65 MPH. For the track just run it through in 3rd gear.
As old as this is I still can't ignore the misinformation. I have a 700R4 with a 3.08 rear and I can roast the 315 tires at will. My car never stalls or even hesitates, it just boils the tires whenever I want. (425HP)
The 700R4 has a 3.06 first gear which makes for a roast happy combination.. It really is more important to be aware of the final drive ratio and the desired rpm's at highway speed.

Happy roasting..!
 

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The 700R4 has a 3.06 first gear which makes for a roast happy combination.. It really is more important to be aware of the final drive ratio and the desired rpm's at highway speed.

Happy roasting..!
In my case that is 2000RPM at 70MPH
That's a very sensible highway rpm range.. For any car that's going to be street driven, overdrive is the only way to go..
 
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