I have a th200 in my 78 mc and a th350 I want to swap out. 350 has a 6" tail shaft. Why is it longer than 200? Will I have to cut driveshaft? Any input be appreciated.
Th200 to th350
- Thread starter Mike Geepers
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Opie Knievel
Rum Fueled Midnight Mechanic and Moderator
If your TH350 has a 6" tailshaft it should be the same length as the TH200. I did this swap in my '86 Monte Carlo.
Thanks for reply Opie knievel, can i ask if you can post some things you encountered as you did the swap? I'm doing it myself and have tried to read up and learn as much as i can before I get overwhelmed.
200 is going out. Rather than rebuild (which I did consider) I opted to swap out with a 350 a friend had, as a quick fix. I really want 700r4, but maybe another time when I'm not so busy
If it is actually a 6" shaft TH350, it should be the same size. TH200 out, TH350 in. Easiest swap to do. Just need the metal vacuum line from the modulator upto a vacuum port on the intake. You'll need a slotted kickdown cable as well.
Opie Knievel
Rum Fueled Midnight Mechanic and Moderator
It's basically one of the easiest swaps you could do. The only thing easier would be swapping in another TH200.
Like Mr. Sony said, you'll need a vacuum line to run from the intake manifold to the vacuum modulator on the rear, right side of the transmission. You may also need a different bracket to hold the kick down cable. It is possible to run a TH350 without the kick down cable hooked up at all but if you do you'll have to manually down shift the transmission and then manually shift back up in situations like passing. Both my Monte Carlo and my Chevy truck have TH350's without the kick down cable hooked up. I'm used to driving them that way. Newer transmissions like the TH200, TH200-4R and 700R4 have a Throttle Valve (TV) cable instead of a kick down cable. You must have the cable hooked up and set correctly for proper transmission operation. Unhooking it or setting it improperly will result in burning up the transmission.
The TH200 is an entirely different transmission that uses a TV cable instead of a kick down cable and it doesn't have a vacuum modulator. The TH200 is weaker than the TH350. There was also a TH350C which has a lockup converter. It typically isn't used for performance applications.
If you run into any problems with the swap let us know. We'll try to help you sort them out.
Like Mr. Sony said, you'll need a vacuum line to run from the intake manifold to the vacuum modulator on the rear, right side of the transmission. You may also need a different bracket to hold the kick down cable. It is possible to run a TH350 without the kick down cable hooked up at all but if you do you'll have to manually down shift the transmission and then manually shift back up in situations like passing. Both my Monte Carlo and my Chevy truck have TH350's without the kick down cable hooked up. I'm used to driving them that way. Newer transmissions like the TH200, TH200-4R and 700R4 have a Throttle Valve (TV) cable instead of a kick down cable. You must have the cable hooked up and set correctly for proper transmission operation. Unhooking it or setting it improperly will result in burning up the transmission.
The TH200 is an entirely different transmission that uses a TV cable instead of a kick down cable and it doesn't have a vacuum modulator. The TH200 is weaker than the TH350. There was also a TH350C which has a lockup converter. It typically isn't used for performance applications.
If you run into any problems with the swap let us know. We'll try to help you sort them out.
Thanks for the clarification
Can you tell me how to identify a 200c
One that has or uses a lockup converter
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