What's the difference between a TH350 and a TH400?
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From: Chi-Town, IL
Re: What's the difference between a TH350 and a TH400? 350 is smaller and meant more for direct drag racing and little street driving...the th400 is bigger and stronger for all around purposes... <img src="gr_stretch.gif" border="0">
If you want to drive on the street more get the TH400, because with the TH350 you will need to rebuild every 6000 miles or so...
If you want to drive on the street more get the TH400, because with the TH350 you will need to rebuild every 6000 miles or so...
Staging Lane
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Re: What's the difference between a TH350 and a TH400? Strength <img src="gr_stretch.gif" border="0"> The TH350 usually goes behind the old 350's and the TH400 goes behind the bigger engines such as the 454,455 etc.
Joel
Joel
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From: Troy, AL
Re: What's the difference between a TH350 and a TH400? I wouldn't say that a TH350 is meant more for drag racing than a 400 is. A TH350 can be made to be a VERY strong transmission (some tranny builders say just as strong or even stronger than a TH400 can be built) that will hold up to alot of abuse for alot of miles. I haven't managed to damage mine yet. I couldn't tell you how many high 9 and low 10 passes it has endured it since installation last summer, but it's ALOT for that amount of time. Street driving would be much easier on it than what I put it through.
Also, TH350s can be had with a lockup converter. Many came from the factory that way (the later model ones.)
The TH350 comes with slightly more desirable gearing. Stock gearing between the two are as follows...
TH350
1st 2.52
2nd 1.52
3rd 1.00
TH400
1st 2.48
2nd 1.48
3rd 1.00
Optional aftermarket gear ratios are available for either. For example, I have a 2.75 1st gear ratio in my TH350.
Other differences are that a TH350 is considerably smaller, lighter, and somewhat easier to turn (saps less power.)
Do I think that a TH400 can actually be stronger? Well, stock for stock, the TH400 is certainly stronger. Once the two are fully performance built, I really don't know but if I had to guess I would say the TH400 could be stronger. What I do know is that I don't yet have enough power to destroy this TH350 so I have no reason to look further at this point. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />
[ January 30, 2002: Message edited by: Colonel ]</p>
Also, TH350s can be had with a lockup converter. Many came from the factory that way (the later model ones.)
The TH350 comes with slightly more desirable gearing. Stock gearing between the two are as follows...
TH350
1st 2.52
2nd 1.52
3rd 1.00
TH400
1st 2.48
2nd 1.48
3rd 1.00
Optional aftermarket gear ratios are available for either. For example, I have a 2.75 1st gear ratio in my TH350.
Other differences are that a TH350 is considerably smaller, lighter, and somewhat easier to turn (saps less power.)
Do I think that a TH400 can actually be stronger? Well, stock for stock, the TH400 is certainly stronger. Once the two are fully performance built, I really don't know but if I had to guess I would say the TH400 could be stronger. What I do know is that I don't yet have enough power to destroy this TH350 so I have no reason to look further at this point. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />
[ January 30, 2002: Message edited by: Colonel ]</p>
Re: What's the difference between a TH350 and a TH400? Interesting point there Col, I recall Jay Billinsgley, one of our sponsors, running a T350 that had a manual lockup. I think it was a 1980's VAN application.
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TECH Resident
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From: NC
Re: What's the difference between a TH350 and a TH400? By the way, A turbo 400 can be built to quite abit more power capacity than a t-350. There was a company in GA that was making them for some 1800hp Pro-mods years back and they actually lived. They dont use them anymore due to alot better clutchless technology now.
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Th400 was behind small engines too 
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
Let's put this ancient thread back to bed. Pointless bump IMO. But, since it's back...
Definitely not the case unless the parts and/or builder are of the lowest possible order of quality/competence, or you're vastly exceeding the build capacity of the trans in question.
Definitely not the case unless the parts and/or builder are of the lowest possible order of quality/competence, or you're vastly exceeding the build capacity of the trans in question.
