Title basically says it all. I believe their pretty much the same size so you only have to move the cross member a bit, bit what else goes into it? Can I use the same torque converter? Do I need to change up shifters?

This is going into a column **** 67 cutlass that had it's original jetaway swapped for a th350. I want to regear the 12 bolt as well from 3.08 to 3.55, but don't want to obliterate the already 11mpg I get.

 

This swap is pretty straight forward. I’m bound to forget or unclearly state a few things so hopefully others can help there. I’ll edit this as I get time to think about it & get posted.

Notes-
1) If you are removing the pan at any point throughout process install a drain plug if there is not one present. Tuning the trans or calibrating speedo requires a pan drop every time.
2) Once your rear gear is set (BTW I vote the 3.55 but IMO 3.73 or 3.91even better) speedo can be calibrated, you can decide on some sort of speedo adapter or to do it by installing proper gears inside trans.
3) Might need a TV cable connecting kit or some carb arm mod in order to connect cable & have proper sweep. There are a number of techniques all over the internet but bottom line is you want TV valve fully open by the time WOT is reached, this is imperative. If anything set cable one or two clicks tight, there is an override spring to absorb the tension. Final cable settings can be played with but you don’t want insufficient travel.

https://classicoldsmobile.com/forums...cruise-147156/

4) As there is potential mish mash of shifter parts I’m not sure what to advise. Set trans in N, set shifter in N & set linkage. That should get you at least P through D & maybe a L, Mods likely if you want S (low gear)

https://classicoldsmobile.com/forums...uestion-64829/

Acquire-

1) Sound 200-4R Trans, Rear Mount & Converter (your 350 dipstick, driveshaft, linkage & tweaked cooler lines should likely work). Converter uses metric bolts so make sure you get them. Unisex & G Body dipsticks not likely to work.
2) Throttle Valve(TV) Cable & Carb bracket
3) Turbo 400 Primary (necessary) & Secondary E Brake cable (can shorten the longer secondary cable (if present) & add a cable stop as an alternative to buying the shorter TH400 type.
4) Some sort of Lockup System control hdwe & wiring (if planning lockup). Most guys use OD only lockup, I like a vac & delay controlled circuit.

https://classicoldsmobile.com/forums/transmission-4/swapping-th350-200-4r-120651/

https://classicoldsmobile.com/forums/transmission-4/2004r-lock-up-138684/

https://classicoldsmobile.com/forums...ontrol-103981/

https://classicoldsmobile.com/forums...nverter-49686/

https://classicoldsmobile.com/forums...s-2004r-60381/

Ops-

1) Install Trans w/ new mount & Converter. Have TV cable & dipstick already installed in trans, might want to zip/wire tie dipstick brkt to appropriate mount hole on trans case & remove it once trans is situated. Crossmember will locate rearward where there are likely mounting holes for TH400. If not there, check xmbr for square & drill holes in frame.
2) Install driveshaft, check yoke location relative to seal, spline engagement & fire/aft travel on output shaft.
3) Space linkage brkt located on frame so cross shaft connects to shift arm & is properly supported in brkt. Spacing typically 1/2” give or take a little.
4) Wire lockup components that are under the car, get wires into upper engine Bay Area for later.
5) I have used TH350 converter covers, they don’t necessarily fit perfect but pretty well. Proper covers are not plentiful, the universal covers suck.
6) Hook up E Brake & cooler lines. Lines will need a bit of tweaking + I think the top/bottom positioning is reverse of TH350 (TBD)
7) Install carb brkt & TV cable. Now would be a good time to confirm your throttle linkage is reaching full WOT, adjust if necessary, then deal with TV.
8) You can run lockup components now or tie them up for later, trans does not depend on lockup to function normally, it simply won’t lock the converter.
9) Fill with ATF as appropriate, type as specified by builder, if unrebuilt trans I would simply use Dexron III. Start car, look for hemorrhages, cycle through gears, confirm proper shifts & adjustments, confirm final fluid level, test drive. Hopefully things cooperate & you simply have some tweaking to do.

 

The torque converters will not interchange. Completely different, even if they physically fit (which I seriously doubt, I have never tried) the 2004R is a lockup converter, the 350 converter is most likely a non lock up style.

 

Good write up :thumbs up: