New one is $225 shipped.
Get one from

RockAuto Parts Catalog

Old one - recycle it.

 

UPDATE

After conversations with Discomike and BPoU, here's the general consensus: If your rig or the parts have 100K+ mi, replace all (water pump, radiator, gaskets, seals, timing chains, wires, RMS, etc.). If it has substantially less, you'll be fine transfering parts, with the exception of those things which are vastly more difficult to do without the engine removed (wires, oil pump, coil packs, timing chain, etc.), and you can focus more on gaskets/seals & such. These lists are not all inclusive...just enough to paint the appropriate picture.

I conceed...never detrimental to replace the radiator (if someone can find me an all-aluminum/non-universal one, I may still do that)/water pump/etc, especially if you've experienced overheating. However, I've got years of life left in these parts in all liklihood with zero issues thus far and have other priorities/bills to consider. My new block has cereamic coated coolant passages, so if sludge does get in there, I'm confident it can be flushed out. Basically, the risk just isn't there to warrant the cost IMO, but everyone's situation will be different. Thanks to everyone for their time & input.

 

Install an Ultra Gauge. The sludge to worry about is in the radiator, fills up the bottom rows and they close off first. A simple test with IR thermometer acan confirm if rad is in good shape, should be under 10F difference on fins top to bottom.