Sounds like the guy didn't want to change valve springs on the heads or something. I'd go to mild solid roller ".550-.575" before lash, throw k800 spring in it and enjoy the season.
Just don't try and shim the lifters solid, I think you have a spring or clearance issue, so address that 1st.
Call Doug herbert for a billet roller, springs to match be it k800 or comp917 ... then buy a crane coated steel gear for the intermediate shaft and get some Morell roller lifters. There are 4 versions and prices. If you go that way you can get out of this for around 700-900 bucks
