The following is just information, not an endorsement of the company or it's products. It was forwarded to me by a friend that used to own a restored 1956 Ford Club sedan;
The company is Barnett High Performance in Laingsbury Michigan:
They list Y-block rebuilt engines, stock & modified & claim they all are given a run in before sale. Also they make tested blocks available.
Also list other Ford engines, including  small blocks, MEL''s & 460's
Contact info is; http://barnetthighperformance.com/292-312-blocks/   or  barnettqc@gmail.com  or Ph# 517-719-5185


Paul