Putting an automatic behind a 235 you have two options, first being one of the two old automatics that were offered behind it, the cast iron powerglide, or the 4-speed hydramatic. Neither compare to modern automatics very well.
The other option is an adapter that allows using a V-8 bolt pattern automatic. Going that route you've complicated the rear motor mount and will have to convert to open drive, probably meaning changing the rear axle.
The 235 and the related motors, the 261, and GMC 228, 248, 270 and 302 all have the bolt pattern and can use the adapters, but if you need an adapter you need the right one, Chevy or GMC because of crankshaft difference. And swapping to a GMC complicates the front motor mount.
Later GM inlines, the 230, 250, 292, don't need an adapter to run the modern automatics, but require new front mounts in addition to rear, and mean you are changing other things too.
And of course modern automatics fall into multiple catagories too, and which you choose may bring more complications.
Give us a better idea what you are trying to accomplish and we might be a bit more helpful...
