1968Cutlassfallbrook

Hello

i was just curare there stall converters for these transmission also what would be a good one for a stock 350 I may install a 4 barrel

joe_padavano

Assuming you can even find a converter, for the money and effort just replace it with a TH350. The 2.52 first gear will make a big improvement off the line.

NTXOlds

I am with Joe. Get rid of the ST300. You will not regret it. I had a local shop replace mine with a TH350, and it was about $1000 out the door.

If you are okay with spending more, search for threads on swapping it for a 200R4. I wish I had done that, but I could not find a shop anywhere near me that could get one at the time while my ST300 was losing about a quart of transmission fluid through the front "seal" every time I drove it.

Someone will correct me if I am wrong, but the 200R4 will bolt right up and use the same driveshaft, but you will have to move the crossmember to the TH400 location and change your e-brake cables to the TH400 cables. It gives you an overdrive along with an even better first gear. The only downside is that they can't take BIG power, but if you are not doing more than modest modifications to your stock 350, you should be fine.

edzolz

With some mods a 2004R will take anything an Olds 350 can dish out. The Buicks with Turbo 6 cylinders sure make big power.

matt69olds

Get a Grand National servo (or aftermarket equivalent) a good shift kit, and careful installation and adjustments is all you need. A 200R4 in good condition with the mentioned upgrades will handle 90% of the small block Olds on the street. A stock remanufactured Grand National or aftermarket equivalent converter would be great for a mild Olds engine.

The lower first gear combined with overdrive will give you the best of both worlds. It will feel like the engine has an extra 75hp over the 2 speed it has now, and will cruise on the highway much better than it does now.

NTXOlds

Yes, listen to @edzolz and @matt69olds . If you intend to rebuild your 350 for a lot of torque and HP, the 200R4 is still a good choice with the mods that they suggested.

joe_padavano

True, there are 9 second GNs that run 200-4Rs. I do sometimes wonder if they survive better behind turbo motors that probably have less low RPM torque and more high RPM HP than a traditional BBO.