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What's the difference between a TH350 and a TH400?

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Old 01-29-2002, 02:37 PM
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Default What's the difference between a TH350 and a TH400?

What is the difference in them? Thanks.
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Old 01-29-2002, 03:53 PM
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Default 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...
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Old 01-29-2002, 05:06 PM
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Default 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
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Old 01-30-2002, 12:43 AM
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Default Re: What's the difference between a TH350 and a TH400?

Just a note. the th400 guts were used in the older JAGS. hhmmmmm
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Old 01-30-2002, 09:22 AM
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Default 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>
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Old 01-30-2002, 03:49 PM
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Default 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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Old 01-31-2002, 07:03 PM
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Default Re: What's the difference between a TH350 and a TH400?

P.I. sells lockup kits for t-350 and t-400's.
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Old 01-31-2002, 07:05 PM
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Default 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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Old 05-13-2018, 05:45 PM
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Default Th400 was behind small engines too

Originally Posted by C5 Hardtop
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
My first truck was an 88 regular cab short bed Chevy and it had a 305 backed by a th400
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Old 05-13-2018, 06:08 PM
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Originally Posted by Fishmaster5
My first truck was an 88 regular cab short bed Chevy and it had a 305 backed by a th400
sorry bud but the last post in this thread was 16 years ago.
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Old 05-13-2018, 06:16 PM
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Originally Posted by 98CayenneT/A
sorry bud but the last post in this thread was 16 years ago.
I saw that right after I posted it
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Old 05-13-2018, 10:23 PM
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This has to be a record
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Old 05-14-2018, 02:37 AM
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Let's put this ancient thread back to bed. Pointless bump IMO. But, since it's back...

Originally Posted by BIGBOS
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...
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.
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