Well those guys were crazy high. Let go with a not to exceed 15K bracket for a motor... anything out there in that range?
I have found a lot of 351 Windsor builders, but 351 Cleveland's not so much...
Any good Ford guy should be able to help you.
where are you located?
I do my own assembly but use Charlie Buck (Buck Racing engines) or Hollis Page (HP engines) for Machine work and balancing. Im a Cleveland guy but I would do a Windsor if I was starting mostly from scratch. CNC Motorsports will sell you a 605hp 438W for 12k. Not sure of their quality though.
Doubtful you'll find a crate Cleveland, I would look for a well respected machine shop with Ford experience. Check out TrackBoss Products for a stroker kit with top quality parts. Tim might be able to recommend a builder in your area. There's also a guy in Stallion Springs, CA - Billy Ray Morgan, who does a lot of Cleveland work. He's in most of the 351C oriented FB groups.