Car Corner
Turbo 350 Wins

November 1, 2002
By Scott Lewis

It feels like a very long time since the transmission in my 67 Camaro RS Convertible stopped working. I have covered the topic here twice before on the choices I had for replacing the ailing two speed Powerglide. In the end the TH350 won out. I had hoped the new transmission would be in the car by the time this went to press, but unfortunately I did not have enough time to meet that deadline.

So this month I will just describe the reasons the TH350, a 3 speed automatic, beat out the 700-R4, a four speed overdrive automatic. Next month I will detail the installation of the TH350 in my 67 Camaro RS Convertible.

Why the TH350

There were a number of reasons I went with the TH350. In the end it came down to cost. The car was not drivable. Money is tight. And I really miss driving the car. I could barely afford the $600 to put the TH350 into the car. If I was determined to wait until I had enough money to put the 700-R4 into the car I would have to wait until March at the earliest (and probably at the compromise of not getting a new computer in March). Even then there is no guarantee that I would be able to afford it with other priorities that may come up between now and then.

Getting the car on the road was the main priority here. Since this is a classic car that I intend to own for a long time, I can always add an overdrive transmission later.

Why Not the 700-R4

Actually there were other reasons to by pass the 700-R4... mostly they had to do with cost. First was the driveshaft. To fit the 700-R4 into the Camaro I would need to have the original driveshaft shortened or have a new driveshaft built for the car. I am sure I grossly underestimated the cost of the driveshaft expense when I came up with my original estimate. If the driveshaft was too far off my guess I would have gotten a lot of flak for it.

Next was the TV-cable (throttle valve). This is a cable that connects to the throttle and tells the transmission how much throttle you are using at any given time. The transmission uses this to determine when to shift and how hard. If you are at full throttle it will shift later and harder than if you were just moseying along at a light cruising speed. This cable's adjustment is critical to the performance of the 700-R4. The problem for me is that they sell TV cable kits... for popular 4 barrel carburetors. I have a 35 year old 2 barrel carb. I would have to A) fabricate something, B) modify a $90-100 TV-cable kit to work with my carb, or C) put a 4 barrel carb on my car. Of course a four barrel carb requires a four barrel manifold. This was not in the financial plan for a 700-R4 conversion. If I had to tell my wife that I needed a new four barrel carb (about $200-300 depending on what model I got) and a new manifold ($100-200), I would be sleeping in the dog house. And I don't even have a dog.

The 700-R4 could and would have easily gone over budget. I couldn't have that at this time. So it was decided that I would stick to the TH350 and drive like normal people in classic old cars. After all the TH350 was an available option in this car.

The 200-4R Factor

I have been getting more and more excited about this option. From what I have learned this transmission would be able to install in the Camaro using a TH400's (the heavy duty three speed automatic) cross-member with minimum modifications. Also it uses the same yoke and driveshaft as the TH350. Finally it is not an electronically controlled transmission. This means it should be a perfect choice for my car.

When I order the TH350 from my brother-in-law's brother I will talk to him about this transmission. I want someone that is familiar with this transmission and what it takes to get it to handle a V-8 (even a mild one). If I don't mind spending the money (much later down the road) I can always buy an Art Carr built 200-4R. Assuming the cost of a beefed up 200-4R was reasonable this is my best choice.


Next month I will show you all I did to get the Powerglide out and the TH350 into my 67 Camaro. Stay tuned...