TH400 with mild 350?

[Mikej89]

I've seen lots of cars with a TH400 and only a mild 350, so was wondering why that is. From what I've heard the TH350 is very tough and can probably handle a mild stroker sbc and limited slip differential with no upgrades. The only possiblity I could think for why I see this so much is maybe the TH400 has a higher 3rd gear ratio for street use. Also they usually cost the same.

 

[chevy2480]

They both are 1:1 ratio 3rd gear. I run a Th350 in my wagon running a 406sbc running 11.18. I know a few guys going 9's on th350. I think most tend to go th400 due to the ability to handle alot of torque and Hp with little work done to it. I say most people with mild motors in my area go with a 400 because they think putting a cam and intake gives them a 1000hp

 

[lilbowtie]

It's probably just personal preference. The 350 is a lighter and takes less hp to turn. Both transmission can be built to handle hp but In stock form the 400 is the tougher trans. My first trans years ago was a 350 with a shift kit and the first time out I broke the intermediate roller-clutch outer race. Switched to a 400 and haven't hurt one yet.

 

[olds307 and 403]

You hit the nail on the head, the TH400 is strong even stock. The TH350 stock died behind mid 70's smog powered 350's. I have seen two dead behind non abused mid 70's Olds Cutlass. If you want to spend dollars on a weak trans, save twice as much for a 2004R. I must say I got over 400,000 km out of a TH250C behind an Olds 307. I toasted it the first time out with a mild 403.

 

[williamattop]

IMO I think at the end of the day its because they are very durable (in most cases) and plentiful in stock form for competitive prices.
Being one of the easier trannies to rebuild/mod helps too.

 

[DoubleV]

IMO, most people running th400's behind mild engines are doing so because they mistakenly think it's the better choice over a th350. It does crack me up when I see people putting them behind smogger 350's, 307's, and 305's.

 

[-83MONTESS-]

The TH400 is the strongest trans you can get for the dollar. I have run one behind my 350, 355, 400, and my future 496 big block. I didnt run it behind the smaller engines because I felt I needed it I used it because it was cheap and I knew it would survive anything I could possibly throw at it with those engines. Its the peace of mind for me.