i have a brand new 700r4 and im thinking of putting it in an 85 trans am or should i go with a th 400 the trans am has a sbc 400 built with lots of power. which tranny if shift kit instaled will hold up better.

 

Either can be built to take whatever you throw at it?

The question is, do you want overdrive? Do you want a lower first gear?

I don't honestly know why people even run TH400s in street cars anymore. There is no advantage. They are heavier, use more hp to turn the driveshaft, and have no overdrive. For a racer on a budget, maybe. A street car, no way. The mileage is worth the price of hd parts that you have to use.

 

I'm a firm believer in the 700R4 But lets face it the 400 Turbo is the stronger tranny by far. You can have the 700R4 beefed up but thats more money. For strength the 400 for drivability the 700. If cost isn't an option a 4L80E or T56.

 

i have a turbo 400 with a gear vender so i have overdrive or od 3. i actualy have 6 gears but yea ur right it its big and takes up too much power. i originaly had planed to have a twin turbo 350 making around 800hp but automatic. im going to sell my 400 + gear vender and get me a manual trans that will hold up to 800 +hp. im going to post a thread about that too.

 

If it is a good build on a 700R4 it will hold up just fine , I am a firm beliver in them also , have one behind the BBC in my 2nd gen '80 , no problems in 2+ years and alot of 1/4 miles

I really can't be sure why people run 3 gear auto's anymore ?

Make sure if you go the 700 route you keep it cool , they hate heat .

Hope it helps

TOM

 

well i can get a 400 cheap that just got rebuilt or i have a 700 laying around i have a 4l80e that needs a rebuild a have a few tranny coolers laying around. iv spent the last year gathering parts but unsure what to run as a tranny? if i was to go the 4l80e how would i run it with out a computer and what would the advantges be?

 

Go with the 700r4

you can build it up just as easily as anything else. Plus why would u try to stuff a TH400 where it doesnt belong? lol

 

To use the 4L80E you would have to get a module for the tranny. It controls the shift points and all sorts of good automatic stuff. It's kind of expensive though. You should be able to find that info from hypertech or any other company that deals with chips and computer programming for cars, and trucks.

 

whent with a good built 700r4 runs sweet!!!!