The value in a engine like that is in the numbers matching restore end of it ,if you just want a engine for power ,i would skip the motor that has set for 15 years ,basically at this point ,its little more than parts that have to be disassembled ...all new gasketts ,possible machine work ...etc.
Just because it ran when pulled 15 years ago ,only means there is no holes in the pistons or block....its more than likely froze solid and will need the bores cleaned up at a minimal.............Imho