The big-block, small-block, and the truck V-6 all have the same bellhousing bolt pattern.
Select the right flywheel/flexplate, and any V-6--V-8 trans bolts up.
From there, it's just a matter of input torque capacity.
I used the same trans that my '88 K1500 came with, after it got rebuilt. Lasted ~18 years, it's at the trans shop right now waiting on another rebuild this coming week.