I just finished mine, and my research showed that some people replaced the top plate with a stainless steel piece, as theirs were cracking. Others made a brace, similar to an exhaust hangar, that tied the front of the FAB to bolt on the engine above.
I did not do either of the above, but will keep a close eye on it. I have a 150HP O-320, and many of the reports of cracking I found were from those with 360's.
Chris