aftermarket pistons come in a variety of compression heights-- and ring packs! so just because it's close to stock magnum, again, doesn't mean that it's correct.
anyway, the *one* of the things i'd be trying to take advantage of is the thinner ring pack on magnum pistons...
anyway, to circle back... if you're saving for a 5.9 stroker i'd be trying to put in the *bare* minimum. as RRR said, snap on a manifold, carb and some headers and just roll with the stock bottom end freshened up.