Its Just Me Posted April 28, 2016 Share Posted April 28, 2016 Has anyone documented the procedure or needed parts etc for swapping a 200R4 auto overdrive in place of a TH350? I know it's a simple bolt in swap, but the devil is in the detail. I bought one from a friend out of his '85 Monte Carlo SS. Low miles and never apart. I know these are the more desirable units to run but I'm wondering what kind of minor upgrades I may need to do to assure reliability and longevity behind my (mostly) stock '72 350, estimated 330 hp max. Will the original parts hold up to normal driving (no racing but maybe a bit of aggressive street driving) or should I be looking into internal upgrades? Would I be $$ ahead to use this as a core & look into BowTie O/D or Extreme O/D units at more upfront money but potential future savings? I plan on running a 3.73 rear ratio and the stock lockup converter. This will give me a 2.50 final ratio. Do I need a special wiring harness or speedo drive unit or anything else to bring this all together? What about the TV cable & brackets (q-jet on edelbrock performer intake). Trans cooling lines...direct bolt up or mods required? This swap won't happen until next winter at the earliest, but I want my ducks in a row before then. Any advice, suggestions or handy hints are welcomed. Real life experience trumps theory. My head is spinning already. Thanks in advance. Scott Quote Link to comment Share on other sites More sharing options...
monte70car Posted April 28, 2016 Share Posted April 28, 2016 Scott swapping the 200r4 in place of your 350 is a direct swap. You might have to move the cross member but your drive shaft will still work. The trans line will screw right into the 200r4 with no issues. Do you have a bench seat or buckets? column shift or floor shift? To make the lock up converter work you will need a cruise control brake switch and the wiring for the trans. Bracket for the TV cable give Bowtie o/d a call they have their TV kits which works great for a q-jet on edelbrock performer intake. I would (have done so on my 700r4 trans and a mild stock 35) install a transmission temp gauge to see what the temp of the trans get up to. Quote Link to comment Share on other sites More sharing options...
cbolt Posted April 28, 2016 Share Posted April 28, 2016 What he said. The most difficult part is the lockup portion. My set up features a lock up controller which you can manually select what speed you want the converter to lock, and a red/green light so you can see at a glance what condition your converter is running. The caveat is the system I have described runs off your speedo at the trans, and right now my speedo isn't working due to an issue with the governor gear inside the trans. (Its in the trans shop today to get this rectified). I tried several different lock up set-ups and the one I currently have was the only one that didn't immediately lock up as soon as the car shifter into OD, causing a bogging condition. Currently I have mine set to lock up at around 50-55 mph. Otherwise, it should be a direct fit. Look at transworks or Bowtie Overdrives for the brackets. If you aren't racing your trans should be able to handle the 350 just fine. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted April 28, 2016 Share Posted April 28, 2016 proper TV cable adjustment is critical! having the proper linkage is a must I want a 200 for behind my 454 I also want to hit the lottery! Quote Link to comment Share on other sites More sharing options...
Its Just Me Posted April 29, 2016 Author Share Posted April 29, 2016 Robert: OEM bucket seats & floor shift...Thanks for the tip on the TV bracket & the temp gauge. CBolt: Can you tell me the manufacturer of your converter controller? I like the idea of adjustable lock up points & a status light. Is there anything special about the speedo hookup (th350 to 200r). Will I need an adapter of some sort? I assume I'll need different speedo gears for the 3.73's to keep accuracy? Sam: Understood on the TV & linkage. I also read something about proper pressures, I better do more homework on that. I expect you'll be looking at a significantly modified 200 to put up w/your 454. Wish I could help w/the lotto. I'm hoping Cory (CKZ03) chimes in... Scott Quote Link to comment Share on other sites More sharing options...
monte70car Posted April 29, 2016 Share Posted April 29, 2016 Scott with the bucket seats and floor shift you will need the O/D lens and the detente. As for the speedo cable as long as the 200r4 is not elec speedo it will work fine. I have 2 Bowtie O/D 700r4 one in my 70 Monte which is behind a big block and a 2.73 rear gear. My trans has a 2200 stall and it moves well for the size of the car. My 700r4 sees temps right around 150° that in traffic with the elec fans on, it does use the cooler in the radiator and then a external cooler before going back to the trans. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted April 29, 2016 Share Posted April 29, 2016 The TV cable is what controls the pump pressure, that's why it so important Quote Link to comment Share on other sites More sharing options...
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