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Tranny Opinons Needed Fast (400 vs 350)

E

elks

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So I thought I had 2 th350 trannies laying around. Instead when I got the one out I soon realized that one is a 400... I had listed them both for sale as a package deal on CL and got a buyer. So I just dug em out and realized that one is a 400. I know totally dumb mistake, but I never paid any attention when i got the 400 pulled out as I was gun ho for 350...

So now I am stuck. I have a th350 in my 72 chevy. It is getting a fresh 350 this spring. I have this 400... So which should I run and why? Are the 400s better in any way? I have to call the guy and let him know I have only 1 350... I could offer the 400 for same money, ask more, or just let him know 1 is for sale... etc... Not sure what to do, first time I pulled this bone head type of move...

the truck is a 2wd and is being built to have good low end power and get off the line fast. It will be a pleasure vehicle only and will not see long road trips etc. It was my grandpas truck so I am 1/2 tempted to keep it stock.
 
400 are stronger and take more hp to run. Unless you are building a race car or big huge motor stay with the 350. Guy will be happy with the 400 let it go.
 
400 is a great tranny. Stouter than the 350. That being said if your running a small block and not towing or anything the 350 will work fine. Personally Id keep the 400. Just my humble opinion.
 
I agree with everyone here but I look at it slightly differently. Yes, a TH400 has more rotating mass and does take slightly more hp to spin, but you will never notice the difference unless you go to the racetrack to measure it, and even then you may not notice a measurable difference depending on your setup and how consistent it is. First gear on a TH400 is 2.48 vs 2.52 for a TH350. Now, a 700R4/4L60(E) will be noticeable with the 3.06 first gear.

You may however, notice the strength of the TH400 when you don't break it.

So I say run the TH400 if you have it.
 
yup, I'll always run the 400 over the 350 despite the first gear and mass.. the durability makes up for it imo... just substantially stouter...
 
OK so he was only interested in the 350 so I am sending it down the road. I had originally asked for the "2" 350 trannies I had for 250 or 150 a piece. I priced em to sell. the money will be used to buy front brakes/callipers etc for my dana 60. So now in stead he will just buy the 350 and I will decide what to do with the 400... I could put in my jeep, but adapting it would take like $700... So time will tell... thanks for the quick replies. I have her all figured out.
 
I will always run a 350 over a 400 in an off road application.

I have seen so many 400s break the tailshaft its not even funny.

Unless you are running a big hp motor I see the 400 as more weight with very little advantage.

I will give you that they are stronger but a th 350 is no slouch either
 
granted, I'm talking hotrods, but I've seen a million 350's that need rebuilds, whereas very few 400's in need of clutches, etc... They just seem to hold up to that abuse MUCH better...
 
blazinzuk said:
I will always run a 350 over a 400 in an off road application.

I have seen so many 400s break the tailshaft its not even funny.

Unless you are running a big hp motor I see the 400 as more weight with very little advantage.

I will give you that they are stronger but a th 350 is no slouch either
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I assume you mean the tailshaft housing or the case Eric? I don't see how anyone could break the 32 spline TH400 tailshaft vs a TH350 27 spline. I don't like TH350s in 4x4 applications with any significant power, because you start trying to rock it to get out of the mud or snow, give it some throttle in reverse and snapola, you'll bust the case in the rear where it only attaches with 4 bolts instead of the TH400s 6 bolts on a larger bolt circle. But you can bust any of the cases, especially if your front dshaft doesn't have enough compression travel.
 
ryoken said:
granted, I'm talking hotrods, but I've seen a million 350's that need rebuilds, whereas very few 400's in need of clutches, etc... They just seem to hold up to that abuse MUCH better...
Click to expand...

Anything with a good amount of power will be much better with a 400, but if you are making mild power I don't think its needed, now granted I am not talking about a stock th350 here. Nothing fancy like Kolenes and altos or anything just a simple good rebuild checking clearances and keeping them in spec, using torrington bearings where you can, and most important a good shift kit.

folkenheath said:
I assume you mean the tailshaft housing or the case Eric? I don't see how anyone could break the 32 spline TH400 tailshaft vs a TH350 27 spline. I don't like TH350s in 4x4 applications with any significant power, because you start trying to rock it to get out of the mud or snow, give it some throttle in reverse and snapola, you'll bust the case in the rear where it only attaches with 4 bolts instead of the TH400s 6 bolts on a larger bolt circle. But you can bust any of the cases, especially if your front dshaft doesn't have enough compression travel.
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Yes the tailshaft housing, my experience comes much more from rocks but plenty of snow. The th350 will pull the threads out and I have seen them break at the tail housing, but a 400 is much more prone to breaking the tailshaft housing when you are doing alot of rockcrawling.

The one thing to remember about a TH 350 is when crawling put it in 1st, not drive.

I am not trying to argue that the 400 is not strong it certainly is, just not sure it is as necessary as alot of folks think it is.

The turbo 350 in Horton has lasted 3 years now, the only problems I have had are the stupid stock shift linkage. I beat that truck pretty hard
 
blazinzuk said:
Anything with a good amount of power will be much better with a 400, but if you are making mild power I don't think its needed, now granted I am not talking about a stock th350 here. Nothing fancy like Kolenes and altos or anything just a simple good rebuild checking clearances and keeping them in spec, using torrington bearings where you can, and most important a good shift kit.



Yes the tailshaft housing, my experience comes much more from rocks but plenty of snow. The th350 will pull the threads out and I have seen them break at the tail housing, but a 400 is much more prone to breaking the tailshaft housing when you are doing alot of rockcrawling.

The one thing to remember about a TH 350 is when crawling put it in 1st, not drive.

I am not trying to argue that the 400 is not strong it certainly is, just not sure it is as necessary as alot of folks think it is.

The turbo 350 in Horton has lasted 3 years now, the only problems I have had are the stupid stock shift linkage. I beat that truck pretty hard
Click to expand...

WORD:pimp:
 
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