I'd just buy pistons, rods, new bearings and some headstuds...then have a machine shop do the work...you will use your same crank and block...it will cost the same or marginally more than a new shortblock but you will have a stronger motor...

BEFORE doing any of this...ask them where the leak was? you can check the crank case (rings), coolant jacket (headgasket) and/or valves (torched valved or valve seat)...