59 holiday sedan, which engine fits??

hi, I am looking for a new engine (http://www.oldsmobileforums.com/forums/showthread.php?t=4136#) for my 1959 98 holiday sedan (http://www.oldsmobileforums.com/forums/showthread.php?t=4136#) vehicle (http://www.oldsmobileforums.com/forums/showthread.php?t=4136#), 394 cui, vin 599C06608, hydromatic
Does anybody know which engine (chevi) will fit best??

My engine gets emediatley hot (I think after the long cold winter there is a crack in my cylinder head (http://www.oldsmobileforums.com/forums/showthread.php?t=4136#)), new cylinder heads (http://www.oldsmobileforums.com/forums/showthread.php?t=4136#) I can´t find at least :-(

are new cylinder heads available?? :uhoh:

Thanks
Thomas