i'm going to refresh one of my total stock 1970 340's

would it hurt the value , if i were to sell it in the future if i put in molnar rods and crank with some nice light forged pistons . or should i just keep it 100% factory they ran well when i put them in storage 12 years ago . just wondering what would bring in the most money if i ever did sell it .
Thanks
Unless the bores have had it, to "refresh" an engine you would not normally replace the pistons.