Straightening a crankshaft is a routine procedure for just about any automotive machine shop that welds and grinds cranks. Unless the 216 crank is forged instead of cast, however, it does not belong in a press. Cast cranks are straightened with a hammer. Forged crankshafts are straightened in a press. Put a cast crank in a press, and it will crack! In the shops where I've done this kind of work, we would sometimes straighten BIG cranks, like an 855 cubic inch Cummins, or one of the Catepillar bulldozer cranks by pressing, but straightening most automobile cranks was done with a big lead hammer, with the crank suspended on each end by brass V-blocks.
Jerry
