Several years ago, I got "corn hulled" by parts place after regularly buying from them for at least ten years. My advice on them is "last resort." The place changed management and they started using a lot of chinko parts.
German auto is first rate, but their prices tend to run a little higher on pretty much everything. Plus, freight is never included (as to my knowledge).
Autohausaz.com (Phoenix area) does extremely well with prices and freight after $75. However, they do not always have everything. Usually receive orders here in SD in 4 days.
Partsgeek.com does very well on prices and availablility of items. You always pay freight. Fast shipping at a few days.
Rockauto.com has a lot of stuff and pretty good prices and quick shipment. Just make your choices carefully with them. They frequently have close-outs on random items.
I've checked all the other places recommended here on this forum and I have never seen better than these 4.
Added with edit: If the lifters come out, turn the buckets upside down and rinse out with carb cleaner or gas and rag and inspect the inside of them for cracks. Cracks show up on the inside before they show up on the top. If you have access to magnifying glass or machinist's glasses, take a good look.
I will let other guys advise you on the valve springs. I, personally, have never replaced them in my rebuilds. Some of my heads did have the old ones tested at the machine shop with the special compressors. Some did not.
You also need some of these guys to chime in on valve guides. I have personally never "pinched" valves in one of these engines. If I did, I would be inclined to go with new valve guides. But, we are talking more money (machine shop situation for the most part). It always seemed to me that if a person smashed a valve.....the guide would get a little out of "round" as well. Let someone else talk to you.
One thing I WILL say is NEVER use starting fluid/ether no matter how desperate you think you are. THAT I know personally about
. (It is a long story with a very short finish!). Suffice it to say that 23 to 1 compression engine with prechambers CAN'T handle it. Later, dude!