Hy Diamond_D, the crack is repairable, the two tried and true methods are welding, and stitching. There is also now thanks to chemistry, closing the crack with "liquid steel" it comes in many brands, but it is basically a steel reinforced epoxy putty. As to engine choices a newer 235 or 261 are the easiest replacement choices, a special short water pump or a water pump adapter plate which allows the use of the older style water pump are two ways to deal with the water pump issue. Either of these two engines will allow you to retain the rest of the stock drivetrain, hope that helps.
