[Fasterthanyou]

If you want to freshen up an Lt1 and keep it on the inexpensive side but still make a ton of power look into the Lloyd Elliot LE1 heads/cam package that's your heads ported to outflow the LT4 hotcam kit and with 30lb injectors and headers you'll put down over 380rwhp. His heads and cam is only $1100 plus shipping.
With those miles you MIGHT (don't have too) want to punch out the block 30 over and get some hyp. pistons. The PM rods will be fine for that kind of power. Tear apart the engine and have things like the crank journals checked and polished, bearings replaced and just have it cleaned and checked. If the oil was changed on a regular basis the engine should be fine, only minor scuffs in the cylinder bore at those miles but bearing wear is directly proportional to the oil condition, pressure, and horsepower. Less than 400hp out of 5.7L worth of pistons isn't a lot of specific output so I doubt the engine is far from new.
Things you can do yourself to check the condition of the engine; check the spark plugs, they'll tell you if you're burning oil or not, compression check on all cylinders will tell you how well the rings and valves are sealing, remove valve covers and check the valvetrain for loose parts.