you have to understand that as pistons go, you have performance brands like JE, then you have "performance"
companies like speed pro. for a 30 over chevy 350, you can get a "performance piston" from speed pro with a CR of "about 10 to 1" for 12 bucks. so you could get a set for 96 bucks. now, from JE, a set of "performance" 30 over chevy 350 pistons with a CR ranging from 11.4 to 9.4 depending on the combustion chamber size, is 608 bucks...
now mind you, stuff for a SB chevy is a dime a dozen, and stuff for mopar small blocks cost mopar, presumably because they have to use better stuff to stand up to the power...