200R4 or turbo350?

[Tuggy24g]

Well as some of you may no I recently and still am in the process of putting a 396 big block into my 1986 El Camino. Well I called summitracing.com and ask them about transmission mounts. Well I told the guy I am talking out my stock 200R4 for a turbo 350. The guy told me that I was better off with the stock 200R4 then the turbo 350. Now what I want to know is am I really better off with the stock transmission (200R4) or should I go with the turbo 350? Also will the performance of the 396 big block go down since the 200R4 completely stock is not set up to handle tons of HP?
Thanks for any help
Brad

 

[megaladon6]

IIRC you had a pretty built BBC, right? i really don't see either trans (stock) surviving if you drive it hard. BUT either one can be built to take over 800HP. given that, i'd stick with the 200r4, you'll thank yourself on the highway.

 

[Blake442]

Both can be built to handle the power, but they have to be built...in stock form you'll just ruin either trans, and have to take it back out and have it done right.

That said, I agree and say that the 200-4R is the better bet, you'll be glad you have the overdrive on the highway...especially if you run a taller rearend gear.

 

[84GP455]

As far as the engine goes the Chevy 396 was never used with the 200-4R from the factory therefore i would use the TH350. I think it is stronger and more bullitt proof than the 200-4R. I run a TH400 and would never swap it out for a 200-4R,,, even if it does have the overdrive. My engine can still cruise at 80 with the rpm's only at 2500 or so.
I don't know how young anybody is on this forum but back in my day there was only the TH350, and Th400 for GM, both of which were used with all the muscle cars of the 60's and 70's. There were no 200-4R or metric transmission's to use with these muscle cars. And i don't understand the perception that the Th350 is weak, or it needs to be built up to run with a 396. That is not true, the TH350 was and is a tough transmission. No lockup converters, no overdrive, just pure brutal strength baby! Hell i twisted a drive shaft in half with my Th400, and i am still using it today, it was rebuilt over 15 yrs ago and i've gone through 3 rear-ends!

 

[Blake442]

I run a TH400... My engine can still cruise at 80 with the rpm's only at 2500 or so.

Christ, what rear gears do you have, 2.41's?
I'm running a TH400 as well but with 3.73's, and when the engine spins 2500 rpm I'm only going about 60...

 

[84GP455]

yup that's right i have 2:41's or 273's in it not sure but you don't need 4:11's when you have a big block, the torque makes up for the gears. If you ask me 3.73's are a bit much for a big block. I was told that 3:55's are the tallest that you want to put in your rear if you have a big block, the guy put it to me this way,,,,do you want to go to Macdonalds, or do you want to go to the beach??? with the 3:55's you can do both.

 

[Blake442]

Yeah, the 3.73 might be considered a bit much for the TH400...they're the factory equiptment, but it also had a 200-4R, so the overdrive helped absorb the tall gears...

But in reality, TH400 cars have also left the factory with 3.91's and 4.11's

I've considered something along the lines of a 3.55 or even a 3.42, but for the most part I've been pretty happy with my 3.73's...

Are you still running a 7.5? That might have something to do with the fact that you've gone through three of them...

 

[megaladon6]

and how many HP did those cars have again? hell, a bunch of modern V6's have the same or more. like i said, i believe he's got a pretty well built (500hp+) BBC. that can definately break a 350.
and why does it matter if they didn't have overdrive in the 60's? they didn't have 7000rpm engines with 500hp and 25mpg either. it doesn't mean i'd refuse to use an ls7 in an old musclecar.

 

[Coveted]

if your building over 450whp run a turbo 400 for sure.

 

[84GP455]

whatever,,,,it's all preference isn't it????? Why where they called muscle cars then if they didn't have torque and horsepower?? My buddy has a 10 second Firebird and he is pushing over 500hp and guess what?? he uses a TH350!