OK, so I pulled out my two speed ST-300 the other night. I have a rebuilt TH-400 sitting around, so I figured this would be a good time to put it in. Would I (Should I) be able to use the same torque converter that was in with the two speed? If not, what recommendations do you have for a replacement? I was looking at B&M's, Summit special, etc. I really don't want to spend much or anything at all if possible. Guess I'm looking for the best bang for buck without sacrificing quality.

If you swap in the 400 in place of the 300, I think you will need a new crossmember for the transmission and your driveshaft will need to be replaced or shortened as well. Bruce

also need a different front driveshaft yoke.

i noticed on the TCI website and some others, that some of the converter part #'s cross between the PG, th350, and th400, as well as some others.

judging by this, it might work on either transmission. you'd have to see if it fits on the splines, and check distance from flywheel. maybe someone has actually done it and will chime in.

I made the swap from ST300 to TH400. You will definitely need a TH400 crossmember, a TH400 yoke and shorten the driveshaft about 3/4 inch.

As for converter, I believe it will work, but not 100% positive as I used a new one.

Thanks guys. I know that I needed a crossmember, and they are rather abundant. What about the driveshaft though? Where could I find one? Shouldn't it already have the correct yoke on it? I don't see them in any catalogs, so where else could I get one?

Hopefully someone has tried using the same converter, otherwise looks like I'll be saving for a new one. Do you guys use a normal stall speed or something higher than stock?

salvage yards have the slip yoke.
tci
moser
martel brothers

any driveshaft specialist or transmission specialist should be able to get one. if you take your driveshaft to be shortened, they should be able to get you a yoke. driveshaft specialists can sometimes be found in the yellow pages.

or someone here might have an extra th400 driveshaft.

if you were swapping to a th350, or 200-4r, you wouldn't have any driveshaft issues

IMO dont go any lower than 1600 on the converter. if the 2spd converter has a 3 or 4 digit GM code on it, and/or a part #, i might be able to tell you it's stall speed. i think the 2spds might have had a decent stall to get the low torque first gear moving, so hopefully you can reuse it.

unless you have a really hot cam in there, you probably wont want to go over 2000-2200 stall speed.