200-4R or TH350C?

Coltrane

Apprentice
Jul 6, 2020
58
33
Hey everyone! This winter I'm going to be digging into my Monte ('85ss) and swapping in some stuff from my other car that was totaled 10 years ago. I'll be putting in my motor (started as a ZZ4, and now has forged internals, will have AFR heads and a cam to match, 750 Holley DP, etc.) but had some questions about the transmission.

I have the TH350C from my '84ss (along with the driveshaft, crossmember, etc.) with a 3400 stall that worked great in that car (ran 12.3@110, and that's before the new heads/cam). I'm just wondering if I should swap that into my 85 or if I should leave the 200-4r. I know that the overdrive trans is better for cruising, but I had 3.90s and a 26" tire with the TH350C and didn't mind having no OD at all (didn't really go over 55 on any highway!) I'm shooting to have around 400hp to the tire (had 320 with the stock ZZ4 heads and baby cam) and I'm pretty sure the stock 200-4r cannot hold up to that.

Here's what I'm really asking - should I keep the 200-4r (and therefore I assume have to have it built and put a new converter in it - any ideas on cost??) or just swap in the TH350C?

Thanks in advance!
 

g0thiac

G-Body Guru
Sep 6, 2020
545
63
Hey everyone! This winter I'm going to be digging into my Monte ('85ss) and swapping in some stuff from my other car that was totaled 10 years ago. I'll be putting in my motor (started as a ZZ4, and now has forged internals, will have AFR heads and a cam to match, 750 Holley DP, etc.) but had some questions about the transmission.

I have the TH350C from my '84ss (along with the driveshaft, crossmember, etc.) with a 3400 stall that worked great in that car (ran 12.3@110, and that's before the new heads/cam). I'm just wondering if I should swap that into my 85 or if I should leave the 200-4r. I know that the overdrive trans is better for cruising, but I had 3.90s and a 26" tire with the TH350C and didn't mind having no OD at all (didn't really go over 55 on any highway!) I'm shooting to have around 400hp to the tire (had 320 with the stock ZZ4 heads and baby cam) and I'm pretty sure the stock 200-4r cannot hold up to that.

Here's what I'm really asking - should I keep the 200-4r (and therefore I assume have to have it built and put a new converter in it - any ideas on cost??) or just swap in the TH350C?

Thanks in advance!
If you want OD, and go on the highway lots, choose the 200, or if that doesn’t bother you then 350.
 

Kamloops cutlass

Greasemonkey
Jan 27, 2021
146
43
Kamloops bc
If you’re ok with the th350 why bother changing it out? it is a stronger unit
Personally I would prefer the OD trans especially with 3.90 gears
But I’m impatient and want to be able to pass people on the highway and still be able to afford to put fuel on it
 

Coltrane

Apprentice
Thread starter
Jul 6, 2020
58
33
If you’re ok with the th350 why bother changing it out? it is a stronger unit
Personally I would prefer the OD trans especially with 3.90 gears
But I’m impatient and want to be able to pass people on the highway and still be able to afford to put fuel on it
Well the 200-4r is what's in there currently, so I'd be changing out to the TH350C - I guess I'm wondering if it's worth the cost to build the 200-4r that's currently in there. I don't know HOW much I'd have to have it built to hold 400hp/400tq to the wheels, so I guess a better question is "how much would it cost to have my 200-4r built to hold that power + converter?"
 
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Kamloops cutlass

Greasemonkey
Jan 27, 2021
146
43
Kamloops bc
Well the 200-4r is what's in there currently, so I'd be changing out to the TH350C - I guess I'm wondering if it's worth the cost to build the 200-4r that's currently in there. I don't know HOW much I'd have to have it built to hold 400hp/400tq to the wheels, so I guess a better question is "how much would it cost to have my 200-4r built to hold that power + converter?"
A buddy of mine used to go through a stock 200 every season behind his regal’s 455
He figured it was cheaper than a rebuild lol
I don’t know, but if I had to guess a performance rebuild would be about 3k out the door
 

Coltrane

Apprentice
Thread starter
Jul 6, 2020
58
33
A buddy of mine used to go through a stock 200 every season behind his regal’s 455
He figured it was cheaper than a rebuild lol
I don’t know, but if I had to guess a performance rebuild would be about 3k out the door
😂 I guess if you just have a good supply of them, go for it!

I'm leaning (heavily) towards just putting in the 350 I have - it's ready to go, has the converter, etc. so why not.
 
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ck80

Comic Book Super Hero
Feb 18, 2014
3,268
113
😂 I guess if you just have a good supply of them, go for it!

I'm leaning (heavily) towards just putting in the 350 I have - it's ready to go, has the converter, etc. so why not.
If your idea is to go with:

1) what's strongest,
2) for the least money,

And

3) don't care about highway use or gas mileage

Then the existing th350 is your best bet. But if it's been sitting untouched for 10 years there may be some seals that have shrunk while its been laid up, so, you may need to address that.

You could pay to update the 200 once and be done, but, it isn't a $500 job. By the time you invest in a converter, full rebuild, plus tax and freight to/from a reputable builder it's probably around $2500-3000 all in.
 
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Coltrane

Apprentice
Thread starter
Jul 6, 2020
58
33
If your idea is to go with:

1) what's strongest,
2) for the least money,

And

3) don't care about highway use or gas mileage

Then the existing th350 is your best bet. But if it's been sitting untouched for 10 years there may be some seals that have shrunk while its been laid up, so, you may need to address that.

You could pay to update the 200 once and be done, but, it isn't a $500 job. By the time you invest in a converter, full rebuild, plus tax and freight to/from a reputable builder it's probably around $2500-3000 all in.
Thank you for the info! If I go with my 350, I'll be taking it to a shop to have it gone through to make sure it's ready before throwing it in there.
 

Coltrane

Apprentice
Thread starter
Jul 6, 2020
58
33
In my opinion, regressing to a three speed transmission is a big step backwards. Invest a little money in the 200 4R or just buy one already built. Don’t be cheap.

Is that specifically for the OD function? (serious question) It will most definitely not be any kind of daily driver, and I just want something strong to take a big beating at the track.
 

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