I agree with every thing he said... THe bold part, I strongly agree with, I will not put anything other than Fedral/Mogule (Supplier of NAPA engine parts) engine parts into my rebuilds... Also Napa has several different kits to offer, Re-Ring kits, Rod bearing Kits, Cam Kits, and so on and so forth that you can mix and match to get the best price on all the parts you need.If cost is a concern, consider not getting the rebuild kit. If you have the ability to do so, tear down your engine before buying the parts and assess what you really need to replace. The rebuild kit comes with a lot of things that you don't necessarily need.
Pistons for example, they don't wear against anything except the rod pin. Unless you have a problem with them, they're probably fine with a re-ring.
If your cam looks to be in good shape and you didn't have a collapsed lifter knock, disassemble and clean your lifters with an ultrasonic cleaner, just be sure to reassemble them with a good assembly lube and don't mix/match parts.
As far as sourcing those parts, unless you're going to order them online, your local parts house will most likely only have only a few suppliers. For bearings and internal parts such as that, I go to Napa.