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Author Topic: 350-400 tranny swap  (Read 3084 times)

Offline hogwild

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350-400 tranny swap
« on: October 09, 2008, 09:48:50 pm »
what are the diffs between 350 and 400 tranny, 86 swb has 350 and i can get 400 cheap . what needs changed? converter the same?
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1986 sb 406 ci
2003 mud buggy 1300 hp 528
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Offline TexasRed

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Re: 350-400 tranny swap
« Reply #1 on: October 09, 2008, 10:15:16 pm »
Different converter, different yoke, probably change the transmission mount and possibly change the driveshaft length.

Oh yeah: the 400 is a tougher transmission but it takes more HP to spin up so a th350 can be better for some stuff.
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Online VileZambonie

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Re: 350-400 tranny swap
« Reply #2 on: October 10, 2008, 06:43:48 am »
You'll need to hook up the detent solenoid too.

A 12v switch on the gas pedal is necessary for forced downshifts.
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Offline HAULIN IT

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Re: 350-400 tranny swap
« Reply #3 on: October 10, 2008, 08:10:38 am »
If this is for your 4x4, the transfer case needs added to the list.
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Offline lowbucktruck

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Re: 350-400 tranny swap
« Reply #4 on: October 10, 2008, 10:51:17 am »
If it's an early model 1970's truck, I think you can swap a TH350 for a TH400 without having to shorten the driveshaft, as long as they are both short tailshaft trannys.  GM's idea.  Early model TH400 truck trannys are short tailshaft.
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