Hey guys, I just swapped a 200-4r, (200r4) into my 1970 Monte. I haven't seen any real detailed threads on that subject, so I wanted to let you all know what was exactly involved, in case anyone was on the fence with doing it.
First my set up.
1970 Monte Carlo. Car originally came with 300hp 350 and TH350 trans with 2.73 gears. (Which numbers match and I still have) Over the years I had migrated to a 400 cu in engine and reworked the Turbo 350 with shift kit/transpack and was running a 3000-3200 stall converter and 4.10 gears. With that combination the car was running around 12.20's with slicks and open headers. I did not, however like the way it drove. It obviously had good power, but felt mushy due to the high stall and the RPM’s on the highway were around 3200 at 55 mph. The engine was always turning 3000 or higher and it I just wasn’t enjoying it. My car has about 78k original miles on it now, and I probably only added a couple thousand over the last 10 years due to the setup I was running.
I decided this winter I would get it back on the road with a more modern transmission setup and freshen up the engine while I did that. (Which turned into a nightmare, but that will be a different story) I did much research and decided to go with a Stage 3 200-4r from Bowtie Overdrives. I was right on that 450 HP limit, so I did decide to be safe and get the stage 3. I chose the 200 because I was nervous that the super low 1st gear on the 700r4 would make the car behave poorly in low with the 4.10 gears. In the past, when launching the car at the strip, I could only leave the line at 1500 rpm’s or I would spin the slicks, so I didn’t want to aggravate that issue. I also chose the 200 because of fewer modifications to the car than a 700, but there were still things that I did have to change out.
I ordered the complete set up from Bowtie with a 2400 stall, the TV made easy system and the installation kit. I also added their custom cooler lines at a later point, along with a larger trans cooler.
Total cost was just under $3000 for this project.
Things that you can expect to stay the same from the Turbo 350:
Entire engine assembly, including the flywheel. You will have to plug the vacuum line that goes to the transmission, and can eliminate that tube. When I mounted up the trans to the engine, I had a 5/16 gap between the flywheel and the converter, so I also needed 3 hardened machine washers I got from Fastenal to reduce the gap to less than ¼”. Transmission mounts; You will need to move the crossmember back to the farthest rearward holes in the frame. The block that mounts between the crossmember and the trans will also work, but you will need to use metric bolts to connect it to the transmission. You can use the same dipstick from a th350, but you will have to etch in a new full mark, because the stick itself is shorter. (easy)
Things that need to be changed:
Kick down set up. OD transmissions use a Throttle valve/cable to control shifts and trans functions. I used the TV made easy kit which included everything I needed cable wise and carburetor linkage wise ( I run and Edelbrock ) I did have to modify my throttle cable mount to fit onto the TV made easy kit, and would probably get the kit they have with the throttle bracket built in next time. The drive shaft length is the same, however, I did need change out the front yolk because my factory one had a large collar on it that would not fit over the tailhousing of the 200-4r. I bought that from Summit for 60$ ish. My kit came with a new plastic flywheel cover, but it did need to be trimmed to fit. There is a bit of wiring needed to make the trans lockup function but you can get by with only 1 wire to the transmission. I routed that through the hole in my trans tunnel that my shifter cable went through, then under the carpet to the dash. I was running a Hurst V-matic 2 shifter with my old set up. I tried to modify it to make it work for a 4 speed auto, but just couldn’t get it to work perfectly so I decided to swap that out also. I went with a Hurst Pro-matic for 700r4/200-4r. This used the same mounts as the old one and works perfectly. I did not opt for the taller truck model, and it works good for me. I would recommend getting a new set of cooler lines made for a 200. I tried to reuse my old ones, but they need to be bent so much that they looked terrible. Plus they were too close to the headers.
If you were just doing this swap and no engine work, you could probably get it done it done in a weekend if you didn’t have any problems.
The set up was not too difficult. You attach a pressure gauge to the pressure port on the drivers side of the trans. It is fairly easy to get at. You need to verify the trans is making the pressure needed in a few different scenarios and that the TV cable is working properly. That’s about it.
I did have some issues with the TV operation and getting it set up correctly. My valve stuck during a test drive, so I needed to take the pan off and fix that. Ended up doing it twice, as after the first fix I wasn’t building enough pressure and had to add some spacers to the internal spring. This was all easily detectable during set up because of the pressure gauge, and the guys at Bowtie did talk me through the steps to correct my problems. Once it is set up according to their procedures, they do warranty the product which is nice.
As of now, everything works properly and the transmission runs at about 150-160 degrees during normal driving. I did add a larger cooler from Summit after my stock radiator trans cooler. This was needed to keep it at the cooler temps they want to see.
I hope this helps, and if anyone has any specific questions, I’d be happy to try and answer them.
