Hemmie,
You can get whatever springs you want, but the heads set up with roller springs are a bit more expensive. The heads I got are #110 on the seat. The guy I got them from recommends them for .525 lift, but he said that is just to be on the safe side and they will handle .550 without issues.
Like I said, I will check them over before installing them.
Here is a link to the heads he is selling, but he has raised the price $25 since I ordered mine.
http://cgi.ebay.com/ebaymotors/ws/eB...category=33617
Chris
Edit:
I just got an email back from another guy who bought the heads from Yoder. He said he had no problems and they made 550HP on a 390ish cid small block and ran them this whole season on a drag car without issue.