Someone with more knowledge may jump in...but I understand that a 235 crank will go in a 216. Bore & stroke: 216 3.500 x 3.750, 235 3.563 x 3.938. The bearing journals are the same diameter, rod and main respectively, for the 216 and 235. Old hot rod books from the early 50s, like California Bill's, describe this transplant. The rods have the same center distance. The block/deck was just 3/16" taller for the 235 than the 216. Apparently it was common to rebuild 216s and machine the rods for insert bearings in the old days, and those replacement bearings are still available at Jim Carter's and other vendors. The problem with the 235 crank in a 216, as I see it is the deck height. The top of the piston will stick up above the top of the block 3/16" unless you have special pistons that are shorter from the wrist pin center to the top. I don't know if they are still available. If so, it would be a cool way to convert to full pressure rod oiling and increase displacement.
I would recommend a reprint Chevrolet Shop manual for your vehicle. I know the truck manuals are available from most of the vendors. Good luck.
Edit: Revisiting this old thread to correct my mistake. The pistons will stick up above 3/32 instead of 3/16. The difference in strokes is 3/16 between 216 and 235 and half of that is the radial difference which is 3/32.
