Check out www.v8engines.com
, the guy has a lot more experience with the engine than most of us. You're totally correct that replacing the cam at the same time as the lifters is a good idea since usually if a lifter is shot, so is the lobe it's riding on.
He raves about Crower cams. RPI is pricey pricey from what I've seen. Either way, make sure to get the matching springs if it's a non-factory cam.