I'm putting an ST400 in my '67 SportWagon that originally came with the ST300. Does anybody know what the difference in the mounting point location is between the two so I can add the bracket to the boxed frame now, before the engine is ready? I found this reference (https://www.tciauto.com/tc/trans-dim/) and I think the ST300 and TH350 have the same mount dimension, but don't know for sure. The FSM doesn't differentiate between the two transmissions in the frame dimension section. Any help appreciated. Thanks.
Did the wagon have a long tail trans? The st400 is longer than the st300 so the crossmember will have to be shifted rearward. The frame should already have the mount locations for the st400 since it was avail on the GS400 and Sportwagon 400 (340 cid with st400 trans). Driveshaft will have to be shortened too.
With a non-boxed frame you should be able to move it back and drill new holes, or, you could get a 400 cross member. I think it's about 6". You'll also need to shorten your drive shaft and go with the larger 400 drive shaft yoke.
