TH350,400, or 700R4/ For BB HP?

[eedgell]

All the auto guys out there. Will all these auto transmisions handle BB torque? I hear " dont use a TH350 with a BB, a TH400 is much better". "Or, dont put a BB in front of a 700R4, it wont take it". What have you all found to be the truth? I am a SM465 kinda guy, but I would like to know the truth about autos.

[keiths69swb]

It all depends on how you drive it.. I had a TH350 behind a pretty stout 396 in high school and never had any problems with it. I currently have a 454 with a TH400, again with no problems. But I know of friends that have had many problems with both. I've never been known to drive things easy but I don't drive stupid either, unlike some of my friends. The 700R4 can easily handle the power, but it needs to be built right. I wouldn't trust a stock one behind a rat motor. Good Luck!!!

[The Big Green]

700r4 would be best imo after you put about a grand maybe more in it.

[WorkinLonghorn]

I agree with Keith above.The 700 R4 can be built up to take major torque.Likewise there are ways to build an "RV" TH 350.For the money and for the long haul I'd go with the TH400.

[The Big Green]

For the record...I've seen them all come apart but that don't stop me from getting any of them...there all good. Its just like our engines there only as good as we build them, if you do it wrong it wont hold up. I built a 350 when I was 16 and it was suppose to be 30 over but when the guy told me he was wrong it was already running, we got it running the same day we picked it up. He was about 8 hours to late. We thought it was loose tourqe convertor bolts...wrong, it was a 30 over looseness...lol...ran like a son of a ***** for 1 year and went to 8 grand by a 16 year old ALOT. It ran great and beat alot of things but when a year pasted it was its time to go and man did it go, 4 broken rods and 3 busted pistons and 1 made its way thru my block. I had 12:1's in that old 355/360 or whatever it was...mixed I guess.

[70cst]

I asked Kurt (who will be restoring my C10 this winter) if I should take out my 400 and install a 700R4 and he said the 400 is more bullet proof than the 700R4 and he wouldn’t think about it. He has built street rods for years and has built up a reputation great body and engine work. There is a reason GM put a 400 behind the BB’s verses the 700R4. I have considered installing a Gear Vendor Overdrive do reduce my rpm's. It still comes down to what you want and as you can see we all have various opinions. Good luck with your choice.

[The Big Green]

He has a very good point, the 400 has almost always been behind the BBC. I have had a 350turbo twice and 400's after that and thats alot of them. With gas prices though the 700r4's overdrive is a good choice.

[67_C-30]

Originally Posted by 70cst

I asked Kurt (who will be restoring my C10 this winter) if I should take out my 400 and install a 700R4 and he said the 400 is more bullet proof than the 700R4 and he wouldn’t think about it. He has built street rods for years and has built up a reputation great body and engine work. There is a reason GM put a 400 behind the BB’s verses the 700R4. I have considered installing a Gear Vendor Overdrive do reduce my rpm's. It still comes down to what you want and as you can see we all have various opinions. Good luck with your choice.

Tell Kurt you can build a 700R4 to be stronger than a stock TH400 for about half of what it will cost you a for $2200 Gear Venders OD. In stock form he's right, but going with the Gear Vendors OD is not cost efficient. The TH400 is power robber as well.

[cnshoot]

how about a 4l80 i know you think electronics but i have seen that they make a box for these for street rod apps so dont count them out and you could use any of the others listed just depends alot on gear and rpm you plan to run what kind of hp and torque all of this is a variable when chosing what kind of parts and most of all converter choice

[Robznob11]

well i like to go fast and for me its a th350 you can get one for 1200 bucks that will hold 900 ponies and its lighter, shifts faster and has less rpm fall off between shifts than the 400, 700 r4 is good for a street rod but comes with calibration problems not to mention there week and need to be built up also to hold power.but if your looking for that od then you probably are not wanting to go real fast like me...

[The Big Green]

Originally Posted by Robznob11

700 r4 is good for a street rod but comes with calibration problems not to mention there week and need to be built up also to hold power.but if your looking for that od then you probably are not wanting to go real fast like me...

My buddy has a 65 Chevelle that pulls the front tires and he has the 700r4 TCI that will withstand alot of horseys everday he claims to get around 16mpg in it with that OD. It is built up and if they are there great tranny's. I still think there all great...come on, there Chevy

[ofnaman]

I have ran them all and built them all. I had a stock 350 turbo behind my 11.5:1 355 with a 125 shot of nos. Lasted for 2 years with many 11 second quarters on it. I currently have a 400 turbo behind my 402 in my pickup and I am not to thrilled with it (shifts funny, although its 37 years old and all original). I personally like 700r4's the best (only for the overdrive). I have used the 700 behind many vehicles with very little problems (but they all were built correctly for the application). My friend and I had a 700r4 behind a 327 with a 150 shot of nitrous and never had a bit of trouble with it, even using the nos in overdrive. All depends on what you want, If your building a big nasty big block I would personally look at the 4l80e also.

[Frizzle Fry]

I'm going with something like this behind the 476: http://www.bowtieoverdrives.com/cata...SUBCAT&CATID=B